WO2005068573A1

WO2005068573A1 - Adhesive film and method for producing the same

Info

Publication number: WO2005068573A1
Application number: PCT/JP2004/019527
Authority: WO
Inventors: Noriaki Kudo; Yasushi Akutsu; Hidetsugu Namiki
Original assignee: Sony Chemicals Corp.
Priority date: 2004-01-15
Filing date: 2004-12-27
Publication date: 2005-07-28
Also published as: TWI265188B; JP2005200521A; KR101151133B1; KR20060123491A; JP5196703B2; TW200525004A

Abstract

An adhesive film (4) having a first resin layer (10), a second resin layer (20) formed on the front surface of the first resin layer (10), and a third resin layer (15) formed on the rear surface of the first resin layer (10), wherein the lowest viscosity in the temperature range lower than the bonding temperature of the first resin layer (10) is higher than the lowest viscosity in the temperature range lower than the bonding temperature of the second and third resin layers (20, 25). When first and second bodies (40, 50) to be bonded are hot pressed while sandwiching the adhesive film (4), the second resin layer (20) flows out toward the outside of the body (50). However, since the first resin layer (10) containing conductive particles (12) does not flow out but stays between the first and second bodies (40, 50), the number of conductive particles (12) sandwiched between first and second connection terminals (42, 52) increases.

Description

Specification

Adhesive film, method of manufacturing adhesive film

Technical field

The present invention relates to the field of adhesives, and particularly to an adhesive containing conductive particles.

Background art

[0002] Conventionally, an anisotropic conductive adhesive film (ACF) has been widely used for connecting electrical components such as semiconductor chips and wiring boards.

[0003] The ACF is formed by forming an anisotropic conductive adhesive in which conductive particles are dispersed in a binder having a thermosetting resin into a film shape, and sandwiches the ACF between electric components. When heated and pressed, the ACF is softened by heating, and the connection terminal of the electric component pushes away the softened ACF due to the pressing, and the conductive particles are sandwiched between the connection terminals facing each other.

[0004] ACF has a thermosetting resin as a binder. If the connection terminals are further heated and pressed with the conductive particles sandwiched therebetween, the thermosetting resin is polymerized and the ACF is cured. Electrical components are electrically connected to each other by the conductive particles, and the electrical components are fixed with the cured ACF.

[0005] For example, even if the height of the connection terminals varies and a gap may occur between the connection terminals to be connected, the gap is filled with the conductive particles. The connection terminals are electrically connected.

[0006] When pressing with heat through the adhesive film while pressing, the conductive particles flow out of the adherend together with the softened solder, so that the conductive property between the connection terminals to be connected is increased. In some cases, the amount of the conductive particles is reduced and the connection terminals are not connected by the conductive particles.

[0007] If the density of the conductive particles added to the ACF is increased, the connection reliability of the connection terminal is improved. However, if the wiring of the electric component is made finer, the connection between the adjacent connection terminals may be increased. Due to the small spacing, the connection terminals that should not be connected may be electrically connected by the conductive particles and short-circuit the electric components. Thus, the connection signal using the conventional ACF is Reliable, it was difficult to obtain an electrical device.

Patent Document 1: JP-A-6-283225

Patent Document 2: JP-A-7-230840

Patent Document 3: JP-A-8-148211

Patent Document 4: JP-A-9-312176

Patent Document 5: JP-A-10-273629

Patent Document 6: JP-A-11 87415

Patent Document 7: JP-A-2000-178511

Disclosure of the invention

Problems to be solved by the invention

[0008] The present invention has been made to solve the above-mentioned disadvantages of the conventional technology, and an object thereof is to provide an adhesive film capable of manufacturing a highly reliable electric device. Means for solving the problem

[0009] In order to solve the above problems, the present invention provides a first resin layer, a second resin layer disposed on the first resin layer, and a first resin layer. A third resin layer disposed on a surface opposite to the second resin layer, wherein the first resin layer has an insulating binder and a conductive resin dispersed in the binder. The insulating binder reacts with the first thermosetting resin by heating and the first thermosetting resin to cure the first thermosetting resin. A first curing agent, wherein the second resin layer reacts with the insulating second thermosetting resin by heating and the second thermosetting resin to form the second thermosetting resin; A second curing agent for curing the curable resin, wherein the third resin layer reacts with the third thermosetting resin by heating and the third thermosetting resin, Third thermosetting resin And a third curing agent that cures the first and second attachment terminals having a first connection terminal and a second attachment terminal having a second connection terminal. When the first and third resin layers are heated and pressed to a predetermined connection temperature or higher, the conductive particles are sandwiched between the first and second connection terminals. An adhesive film configured such that the first, second, and third thermosetting resins react with the first, second, and third curing agents, respectively, and are cured to connect the first, second adherends. Wherein the first resin layer is The minimum viscosity in a temperature range lower than the continuation temperature is set to be lOOOPa's or more and lOOOOOOPa's or less, and the second resin layer has a minimum viscosity in a temperature range lower than the connection temperature that is equal to the first viscosity. The viscosity of the resin layer is lower than the minimum viscosity in a temperature range lower than the connection temperature, and the film thickness of the second resin layer is larger than the film thickness of the first and third resin layers. This is the adhesive film that was obtained.

The present invention is an adhesive film, wherein the second resin layer has a minimum viscosity in a temperature range lower than the connection temperature, which is lower than the connection temperature of the first resin layer. Adhesive film with a minimum viscosity of less than lZio in the range.

The present invention is an adhesive film, wherein the film thickness of the first resin layer is 1Z2 times or more and 2 times or less the average particle size of the conductive particles.

The present invention is an adhesive film, wherein the conductive resin density of the first resin layer is higher than the conductive particle density of the second resin layer.

The present invention is an adhesive film, wherein the film thickness of the second resin layer is one of the first and second adherends which is in close contact with the second resin layer side. This is an adhesive film having a thickness larger than the thickness of the connection terminal of the body.

The present invention is an adhesive film, wherein the minimum viscosity of the third resin layer in a temperature range lower than the connection temperature is lower than the connection temperature of the first resin layer! This is an adhesive film whose viscosity is lower than the minimum viscosity in.

The present invention is an adhesive film, wherein the third resin layer has a lowest viscosity in a temperature range lower than the connection temperature, lower than the connection temperature of the first resin layer. Adhesive film with a minimum viscosity of less than lZio in the range.

The present invention is an adhesive film, wherein the film thickness of the third resin layer is smaller than the film thickness of the first resin layer.

The present invention is a method for producing an adhesive film for producing an adhesive film in which a release film is adhered on at least one surface, comprising: a first release film; and a first release film disposed on a surface of the first release film. A resin layer, a second resin layer disposed on the surface of the first resin layer, and a second release film disposed on the surface of the second resin layer; The minimum viscosity in a temperature range lower than the connection temperature of the first resin layer is the second resin. Exposing the first resin layer surface by peeling off the first release film from the first resin layer of the laminate having a viscosity higher than the minimum viscosity in a temperature range lower than the connection temperature of the layers; A method for producing an adhesive film in which a liquid adhesive is applied to the exposed first resin layer surface and dried to form a third resin layer.

The present invention is a method for producing an adhesive film, wherein the laminate is produced by applying a liquid adhesive on the surface of the first release film and drying to form the first resin layer. After applying a liquid adhesive to the surface of the first resin layer and drying to form the second resin layer, the second release film is attached to the surface of the second resin layer. This is a method for producing an adhesive film.

The present invention is a method for producing an adhesive film, wherein the production of the laminate is such that a liquid adhesive is applied to the surfaces of the first and second release films, respectively, and dried, and the first and second This is a method for producing an adhesive film in which after forming a resin layer, the surface of the first resin layer and the surface of the second resin layer are brought into close contact with each other.

[0010] FIG. 7 shows a case where the resin layer having the thermosetting resin and the curing agent is heated and set from the starting temperature T.

0 schematically shows the relationship between the viscosity change and the temperature when the connection temperature is increased to τ

2

FIG. 7 is a graph, in which the vertical axis represents viscosity and the horizontal axis represents temperature.

[0011] When the resin layer starts to be heated from room temperature (starting temperature T) by heating, the resin layer in the resin layer is heated.

0

It softens and the viscosity of the resin layer begins to decrease. When the temperature of the resin layer rises, the polymerization reaction of the thermosetting resin progresses along with the softening of the resin component.Therefore, its viscosity is the lowest at the temperature τ determined by the composition of the resin layer and its mixing ratio. After reaching the value, depending on the progress of polymerization,

1

The viscosity starts to rise.

[0012] Even when the resin layer contains conductive particles, the viscosity of the resin layer becomes minimum at a temperature higher than room temperature. When the adhesive film is sandwiched and heated, the first and second resin layers reach the minimum viscosity at a certain temperature above room temperature.

[0013] The second resin layer flows out toward the outside of the adherend in the vicinity of the minimum viscosity, but the first resin layer has a minimum viscosity higher than that of the second resin layer. The conductive particles in the first resin layer remain between the adherends, and the conductive particles sandwiched between the first and second connection terminals. The number of children increases.

[0014] The minimum viscosity of the first resin layer can be changed by changing the type of the thermosetting resin, the type of the curing agent, and the blending amount of the thermosetting resin and the curing agent. It can be higher than the layer.

[0015] If the conductive particles whose surface is covered with an insulating coating are used as the conductive particles, the conductive layer of the conductive particles is directly connected even if the second resin layer contains the conductive particles. Since the terminals are not touched, a short circuit between the connection terminals can be prevented.

[0016] The insulating coating is generally composed of an insulating resin, and is easily broken when the conductive particles are sandwiched between the first and second connection terminals. The first and second connection terminals are in direct contact with the terminals, and are electrically connected by the conductive particles.

[0017] Since the thickness of the first resin layer determines the number of conductive particles of the adhesive film 4 of the present invention, high film thickness accuracy is required. Regardless of whether the first resin layer is formed on the release film surface or the second resin layer is formed directly on the surface of the first resin layer, the first resin layer is formed on the release film surface anyway. This resin layer can be formed with high film thickness accuracy.

The invention's effect

With the use of the adhesive film of the present invention, the conductive particles do not flow out in the step of heating and pressing and remain between the first and second connection terminals, so that they are sandwiched between the first and second connection terminals. The number of conductive particles increases. In addition, since the conductive particles are filled with the second resin layer between the connection terminals adjacent to each other, the connection terminals of the same adherend are not easily short-circuited. Therefore, by using the adhesive film of the present invention, an electric device having high connection reliability can be obtained.

Brief Description of Drawings

[FIG. 1] FIGS. 1 (a) to 1 (e) are cross-sectional views illustrating the first half of a first example of the method for producing an adhesive film with a release film of the present invention.

FIG. 2 (f) is a cross-sectional view for explaining the latter half of the first example of the method for producing an adhesive film with a release film of the present invention.

FIG. 3 is a cross-sectional view illustrating an example of a first adherend used in the present invention. FIG. 4 is a cross-sectional view illustrating an example of a second adherend used in the present invention.

FIG. 5 (a)-(d) is a cross-sectional view illustrating a step of manufacturing an electric device using the adhesive film of the present invention.

FIGS. 6 (a) and 6 (b) are cross-sectional views illustrating a second example of the method for producing an adhesive film with a release film according to the present invention.

FIG. 7 is a graph showing the relationship between viscosity and temperature when a resin layer is heated.

Explanation of symbols

[0020] In each figure, reference numeral 1 indicates an electric device, reference numeral 3 indicates a laminate, reference numeral 4 indicates an adhesive film, reference numeral 10 indicates a first resin layer, reference numeral 11 indicates a binder, and reference numeral. Reference numeral 12 denotes conductive particles, reference numeral 20 denotes a second resin layer, reference numeral 25 denotes a third resin layer, reference numeral 31 denotes a first release film, and reference numeral 32 denotes a second release layer. Reference numeral 40 denotes a first adherend (circuit board), reference numeral 42 denotes a first connection terminal, reference numeral 50 denotes a second adherend (semiconductor element), reference numeral 52 denotes a release film. Indicates a second connection terminal.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an example of a process for producing an adhesive film according to the present invention will be described. An insulating first thermosetting resin and a first curing agent for polymerizing the first thermosetting resin by heating are dispersed in an organic solvent, and a binder solution is prepared. The conductive particles are dispersed in the mixture to prepare a liquid first adhesive.

[0022] Separately, the insulating second and third thermosetting resins are separately dispersed in an organic solvent together with the second and third curing agents to form a liquid, A second and a third adhesive containing no conductive particles are prepared.

The reference numeral 31 in FIG. 1 (a) indicates the first release film! The first release film 31 is elongate, and one surface thereof is preliminarily subjected to a surface treatment, and the dried film thickness on the surface-treated release surface is 1Z2, which is the average particle size of the conductive particles. The first adhesive was applied so as to be twice or more and twice or less, and the conductive particles 12 were dispersed in a binder 11 having a thermosetting resin and a curing agent as shown in FIG. The first resin layer 10 is formed.

Next, the second adhesive is applied to the first resin layer 10 such that the film thickness after drying is larger than the first resin layer 10 and larger than the height of a second connection terminal described later. Resin layer applied to 10 surfaces and dried Then, excess organic solvent is evaporated from the second adhesive to form a second resin layer 20 containing no conductive particles (FIG. 1 (b)).

Next, when an elongated second release film 32 is attached to the surface of the second resin layer 20, an elongated laminate 3 is obtained (FIG. 1 (c)). The second resin layer 20 has a thermosetting resin and a curing agent such that the minimum viscosity in a temperature range lower than the connection temperature is lower than the minimum viscosity of the first resin layer. A resin layer having a low minimum viscosity has a low viscosity even at room temperature, and has a high adhesiveness.

Therefore, even when the same one is used for the first and second release films 31 and 32, the adhesive force of the first resin layer 10 to the first release film 31 is the second. Since the adhesive strength of the resin layer 20 to the second release film 32 is weaker, when the force for peeling off the first and second release films 31 and 32 relatively is reduced, the first The release film 31 peels off from the first resin layer 10, but the second release film 32 remains without peeling from the second resin layer 20 (FIG. L (d)).

Next, the above-mentioned third adhesive is applied to the surface of the first resin layer 10 so that the film thickness after drying is smaller than the film thickness of the first resin layer 10. After drying, a third resin layer 25 containing no conductive particles is formed, and an elongated adhesive film 4 is obtained (FIG. 1 (e)).

Next, the adhesive force between the release surface and the surface of the third resin layer 25 due to the surface treatment increases the adhesion between the release surface of the second release film 32 and the surface of the second resin layer 20. A third release film 33 weakened by force is prepared, and this release film 33 is attached to the surface of the third resin layer 25, whereby an adhesive film 4 having release films 32, 33 attached on both sides is obtained. (Fig. 2 (f)). When the adhesive film 4 is wound into a roll, a roll of the adhesive film 4 with the release films 32 and 33 is obtained.

Next, a process of connecting an adherend having connection terminals using the adhesive film 4 will be described. Reference numeral 40 in FIG. 3 and reference numeral 50 in FIG. 4 indicate a circuit board and a semiconductor element as first and second adherends, respectively.

The circuit board 40 has a glass substrate 41 and a first connection terminal 42 formed on one surface of the glass substrate 41, and the first connection terminal 42 is formed on the glass substrate 41. A conductive film is formed by patterning, and in the patterning process, a first conductive film is formed from the same conductive film. A narrow wiring film for connecting the connection terminals 42 is formed.

The semiconductor element 50 has an element main body 51 and a second connection terminal 52 arranged on one surface of the element main body 51. The second connection terminal 52 has a bump shape, 51 are electrically connected to the internal circuit (not shown).

To connect the semiconductor element 50 to the circuit board 40, the adhesive film 4 with the peeling films 32 and 33 is also unwound with the roll force of the adhesive film 4. As described above, the adhesive force between the release surface of the third release film 33 and the surface of the third resin layer 25 is determined by the adhesive force between the release surface of the second release film 32 and the surface of the second resin layer 20. The adhesive force between the second and third release films 32 and 33 is electrostatically attracted, and the force to peel off the second and third resin films 32 and 33 relatively Is applied, the third release film 33 is peeled off from the third resin layer 25, and the surface of the third resin layer 25 opposite to the first resin layer 10 is exposed. The film 32 remains without peeling from the second resin layer 20.

The adhesive film 4 from which the third release film 33 has been peeled off is cut into a predetermined length, and the exposed surface of the third resin layer 25 of the cut piece is placed on the first surface of the circuit board 40 described above. When the surface of the third resin layer 25 is adhered to the surface on the side where the connection terminal 42 is disposed, the surface of the third resin layer 25 is adhered to the surface of the first connection terminal 42 (FIG. 5A).

[0034] The third resin layer 25 contains a thermosetting resin and a curing agent such that the lowest viscosity in a temperature range lower than the connection temperature is lower than that of the first resin layer 10. Since the resin layer has low adhesiveness and high adhesiveness, the circuit board 40 and the second release film 32 are electrostatically attracted to each other, and when a force for relatively peeling off is applied, the second release film 32 is formed. The adhesive film 4 is peeled off, and the adhesive film 4 remains on the circuit board 40 (FIG. 5B).

[0035] The surface of the semiconductor element 50 on which the second connection terminal 52 is disposed faces the surface of the circuit board 40 to which the adhesive film 4 is attached, and the first and second connection terminals 42, The semiconductor elements 50 are positioned so that they face each other, the semiconductor element 50 is placed on the adhesive film 4, and the semiconductor element 50 is pressed by a pressing device (not shown) (FIG. 5 (c)).

The mounting table on which the circuit board 40 is mounted and the pressing device that presses the semiconductor element 50 have been heated to a predetermined temperature in advance, and when the semiconductor element 50 is pressed against the circuit board 40, the heat transfer The semiconductor element 50, the circuit board 40, and the adhesive film 4 are heated to the starting temperature (room temperature). Then, the viscosity of the first, second and third resin layers 10, 20, 25 starts to decrease and reaches the minimum viscosity before the temperature rises to the set connection temperature.

[0037] The second resin layer 20 has a minimum viscosity of less than lOOPa's in a temperature range lower than the connection temperature.

(less than 100OOpoise) is used, so that the second resin layer 20 is a force that flows toward the outside of the semiconductor element 50 before the temperature rises to the connection temperature. The first resin layer 10 is made of a thermosetting resin whose minimum viscosity in a temperature range lower than the connection temperature is as high as lOOOPa • s or more and 3000Pa's or less (lOOOOpoise or more and 30000poise or less). Since the first resin layer 10 does not flow toward the outside of the semiconductor element 50, the conductive particles 12 in the first resin layer 10 remain between the semiconductor element 50 and the circuit board 40. .

Accordingly, when the second connection terminal 52 pushes away the adhesive film 4 by pressing the semiconductor element 50, the tip of the second connection terminal 52 becomes conductive between the semiconductor element 50 and the circuit board 40. The particles 12 are pressed against the circuit board 40.

Since the thickness of the third resin layer 25 is smaller than that of the first resin layer 10, when the conductive particles 12 are pressed against the circuit board 40, the conductive particles 12 The third resin layer 25 is pierced and pressed against the first connection terminal 42, so that the conductive particles 12 are sandwiched between the first and second connection terminals 42 and 52.

The thickness of the second resin layer 20 is larger than the height of the connection terminal 52 of the semiconductor element 50 by a number of zm (0.5 μm or more and less than 10 m). Even if the layer 20 is pushed out of the semiconductor element 50, the remaining second resin layer 20 fills the space between the second connection terminals 52, and the side surface of the second connection terminal 52 and the side of the element body 51. The second resin layer 20 is in close contact with a portion exposed between the second connection terminals 52.

When heating and pressing are further continued, the viscosity of the first, second and third resin layers 10, 20, and 25 starts to increase due to the progress of the polymerization reaction of the first and third thermosetting resins. When the heating is performed until the temperature reaches the set connection temperature, the adhesive film 4 is cured by the polymerization of the first to third thermosetting resins, and the semiconductor element 50 is bonded to the circuit board 40 by the cured adhesive film 4. Fixed.

Reference numeral 1 in FIG. 5D indicates an electric device in which the semiconductor element 50 is fixed to the circuit board 40. Is shown. This electric device 1 is not only a circuit board 40 and a semiconductor element 50 mechanically connected by a cured adhesive film 4 but also conductive particles 12 sandwiched between first and second connection terminals 42 and 52. Are also electrically connected.

As described above, when the adhesive film 4 of the present invention is used, the conductive particles 12 do not flow out of the semiconductor element 50 in the step of heating and pressing, and the conductive particles 12 between the first and second connection terminals 42, 52 Since the number of the conductive particles 12 sandwiched between the metal layers increases, the conduction reliability increases.

[0044] Further, the space between the connection terminals 52 adjacent to each other is filled with the second resin layer 20 containing no conductive particles, so that there is no short circuit between the connection terminals 52 of the same adherend. Thus, the use of the adhesive film 4 of the present invention makes it possible to manufacture a highly reliable electric device 1.

[0045] Although the case where the second adhesive is formed on the first resin layer 10 has been described above, the present invention is not limited to this. Hereinafter, other examples of the production example of the adhesive film of the present invention will be described.

First, in the above-described steps, first and second adhesives are produced, and these adhesives are separately applied to the stripped surfaces of the elongated first and second stripped films 31 and 32, and dried. As shown in FIG. 1 (a), a first resin layer 10 is formed on the surface of the first release film 31, and as shown in FIG. 6 (a), the second resin film 10 is formed on the surface of the second release film 32. Each of the resin layers 20 is formed.

Next, with the surfaces on which the first and second resin layers 10 and 20 are formed facing each other, the longitudinal ends of the release films 31 and 32 are placed between two pressing rolls. While pressing the surfaces of the release films 31, 32 opposite to the surfaces on which the first and second resin layers 10, 20 are formed with a pressing roll heated to a predetermined temperature. When the release films 31 and 32 are passed in the longitudinal direction, the first and second resin layers 10 and 20 are heated and pressed in a state where they are in close contact with each other when the release films 31 and 32 pass between the pressing rolls. Then, the first and second resin layers 10 and 20 are bonded to each other to obtain a laminate 3 as shown in FIG. 6 (b).

[0048] If the first release film 31 is peeled from the laminate 3, and the third resin layer 25 is formed in the same process as shown in Figs. 1 (c) and 1 (e), An adhesive film 4 with a release film 32 having a structure similar to that of the adhesive film 4 shown in FIG. 1 (e) and having an elongated overall shape is obtained. [0049] In the above, the minimum viscosity of the first resin layer 10 is reduced by changing the types of the thermosetting resin and the curing agent used for the first to third resin layers 10, 20, and 25. The case where the viscosity is higher than the minimum viscosity of the second and third resin layers 20 and 25 has been described, but the present invention is not limited to this.

[0050] The viscosity of the first resin layer can be adjusted with a material other than the resin. For example, the type of filler added to the first resin layer, the average particle size, the amount of the filler, and The minimum viscosity of the first resin layer 10 can be made higher than the other resin layers by changing the type, average particle size, and amount of the conductive particles added to the first resin layer. .

Example

Conductive particles 12 are manufactured by sequentially laminating a 0.08 μm-thick nickel layer and a 0.04 m-thick gold layer on the surface of benzoguanamine resin particles with a particle size of 4.0 μm. Further, on the surface of the conductive particles 12, an insulating resin film made of an acrylic Z-styrene / divinylbenzene copolymer resin and having a film thickness of 0.1 111 to 0.5 / zm is formed. Thus, conductive particles 12 having an insulating film were obtained.

[0052] The first thermosetting resin (trade name "Epicoat 1007", manufactured by Japan Epoxy Resin Co., Ltd.) 80% by weight, and an imidazole-based curing agent (trade name "2E4MZ", Shikoku Chemical Industry Co., Ltd.) A 20% by weight binder was dissolved in a mixed solvent of equal amounts (weight ratio) of toluene and ethyl acetate to prepare a binder solution containing 30% by weight of a binder. The conductive particles 12 with the insulating coating thus obtained were dispersed so as to have a desired particle density, thereby producing a liquid first adhesive containing the conductive particles 12 with the insulating coating.

[0053] The first adhesive is applied to a release film and dried to form a film, and the film is used to measure the viscosity of the film at 10 ° C / min with a viscometer (Rheometer RS 150 manufactured by Noke Corporation). The viscosity at the time of heating to the connection temperature (180 ° C) at the heating rate of was measured, and the viscosity that was lower than the connection temperature and became the lowest in the temperature range was determined as the minimum viscosity of the first resin layer 10. Its value was 2000 Pa's. The density of the conductive particles 12 with an insulating coating per unit volume of the film was measured to be about 3 million Zmm ³ . [0054] A second thermosetting resin (trade name "Epicoat 4007P", manufactured by Japan Epoxy Resin Co., Ltd.) 80% by weight, and an imidazole-based curing agent (trade name "2MZ", Shikoku Chemical Industry Co., Ltd.) 20% by weight of a binder was dispersed in the same mixed solvent as the first adhesive, to prepare a second adhesive containing 30% by weight of a binder and no conductive particles. The second adhesive was dried to form a film, and the minimum viscosity of the second and third resin layers 20 and 25 described below was determined under the same conditions as for the first adhesive. was s

Using the first and second adhesives, the first and second resin layers 10 and 20 are formed in the steps shown in FIGS. 1 (a)-(e) and 2 (f) described above. After the formation, the third resin layer 25 was formed by using the same third adhesive as the second adhesive to produce the adhesive film 4 with the release film of Example 1. Note that a roll coater was used for applying the first to third adhesives.

Table 1 below shows the minimum viscosity, the film thickness, the density of the conductive particles with the insulating coating, and the particle size of the conductive particles with the insulating coating of each of the resin layers 10, 20, and 25. Here, the density of the conductive particles is the number of conductive particles contained per lmm ³ of the resin layer.

[0057] [Table 1]

Table 1: Composition of adhesive film and evaluation test results (Example)

2] Table 2: Composition of adhesive film and evaluation test results (comparative example)

[0059] Since the particle size of the conductive particles with an insulating film is in the range of 4.22 µm or more and 4.62 µm or less, the average particle size is 4.22 m or more and 4.62 m or less. In range.

80% by weight of thermosetting resin (trade name “Epicoat 4007P”, manufactured by Japan Epoxy Resin Co., Ltd.) and 20% by weight of imidazole-based curing agent (trade name “2MZ”, manufactured by Shikoku Chemical Industry Co., Ltd.) The adhesive film 4 of Example 2 was produced under the same conditions as in Example 1 except that an adhesive having a minimum viscosity higher than the first adhesive of Example 1 was used as the first adhesive. .

80% by weight of thermosetting resin (trade name "Epicoat 4007", manufactured by Japan Epoxy Resin Co., Ltd.) and 20% by weight of imidazole-based curing agent (trade name "2E4MZ", manufactured by Shikoku Chemicals Co., Ltd.) Consisting of an adhesive having a lower minimum viscosity than the first adhesive of Example 1, An adhesive film 4 of Example 3 was produced under the same conditions as in Example 1 except that the adhesive film was used as an adhesive.

An adhesive film 4 of Example 4 was produced under the same conditions as in Example 1 except that the number of conductive particles with an insulating film dispersed in the first resin layer was increased.

An adhesive film 4 of Example 5 was produced under the same conditions as in Example 1 except that the number of conductive particles with an insulating film dispersed in the first resin layer was reduced.

An adhesive film 4 of Example 6 was produced under the same conditions as in Example 4 except that the number of conductive particles with an insulating film dispersed in the first resin layer was increased compared to Example 4.

To the first adhesive is added silicon dioxide particles (average particle diameter 0.5 m) as an insulating filler to form a first resin layer 10 containing 40% by weight of the filler. An adhesive film 4 of Example 7 was produced under the same conditions as in Example 1 except for the above.

80% by weight of thermosetting resin (trade name “Epicoat 1007”, manufactured by Japan Epoxy Resin Co., Ltd.) and 20% by weight of imidazole-based curing agent (trade name “2MZ”, manufactured by Shikoku Chemicals Co., Ltd.) Example 8 was performed under the same conditions as in Example 2 except that an adhesive having a minimum viscosity higher than the second and third adhesives of Example 2 was used as the second and third adhesives. The adhesive film 4 was produced.

80% by weight of thermosetting resin (trade name "Epicoat 4007P", manufactured by Japan Epoxy Resin Co., Ltd.) and 20% by weight of imidazole-based curing agent (trade name "2MZ", manufactured by Shikoku Chemicals Co., Ltd.) Example 9 was carried out under the same conditions as in Example 7 except that an adhesive having the lowest viscosity higher than the second and third adhesives of Example 7 was used as the second and third adhesives. The adhesive film 4 was produced.

<Comparative Example 1> An adhesive film of Comparative Example 1 was produced under the same conditions as in Example 1 except that the thickness of the first resin layer was 10 m and the thickness of the second resin layer was 10 m.

An adhesive film of Comparative Example 2 was produced under the same conditions as in Example 1 except that the thickness of the second resin layer was 10 m and the thickness of the third resin layer was 10 m.

An adhesive film of Comparative Example 3 was produced under the same conditions as in Example 1 except that the thickness of the second resin layer was 5 μm and the thickness of the third resin layer was 15 m.

An adhesive film of Comparative Example 4 was produced under the same conditions as in Example 8, except that the first adhesive was changed to the second adhesive used in Example 1.

An adhesive film of Comparative Example 5 was produced under the same conditions as in Comparative Example 4, except that the number of conductive particles with an insulating coating dispersed in the first resin layer was increased from that of Comparative Example 4.

An adhesive film of Comparative Example 6 was produced under the same conditions as in Example 1 except that the first adhesive resin curing agent was omitted.

[0074] The minimum viscosity, the film thickness, the density of the conductive particles with the insulating film, the density of the resin particles 10, 20, and 25 in the adhesive film 4 of Examples 2-9 and Comparative Examples 1 to 6, The particle diameters of the attached conductive particles are shown in Tables 1 and 2 above.

[0075] The minimum viscosity of each resin layer was determined by measuring the viscosity of the completed resin layer, not by measuring the viscosity of the constituent material of the resin layer (for example, thermosetting resin) alone. Therefore, for example, when a hardening agent that is not only a thermosetting resin is added, the viscosity of the resin layer with the hardening agent added is measured, and when the conductive particles and the filler are further added, Measured the viscosity of the resin layer with the conductive particles (filament) added thereto.

Using the adhesive films 4 of Examples 1 to 9 and Comparative Examples 1 to 6 described above, the semiconductor element 50 and the circuit board 40 were connected at a connection temperature of 190 ° C., a pressing load of 1960 kPa, and a heating and pressing time of 10 seconds. Were connected to obtain an electric device 1 of Example 1-19 and Comparative Example 1-6. Here, as one of the semiconductor elements 50, a gold bump having a bump bonding area of 45 m × 30 m and a height of 15 m is formed on one surface of the semiconductor element 50 having a width of 1.8 mm, a length of 20 mm, and a height of 0.4 mm. A connection terminal 52) formed at intervals of 40 m was used, and a circuit substrate 40 in which a connection terminal 42 made of a 0.7 m-thick indium oxide film was formed on a glass substrate 41 was used.

[0078] The following evaluation tests were carried out on the electric devices 1 of Examples 1 to 9 and Comparative Examples 1 to 6.

[Number of conductive particles]

The 200-sided bumps of each electric device 1 were also observed by using an optical microscope (magnification: 340 times) on the circuit board 40, and the number of the conductive particles 12 captured by the bumps was counted. Tables 1 and 2 show the number of locations where the number of conductive particles supplemented is the smallest among the 200 bumps.

[0080] [Conduction Reliability]

Using a pressure tucker tester (trade name “EHS-411” manufactured by Tabai Espec Co., Ltd.) for each electric device 1, conduction between the first and second connection terminals 42 and 52 facing each other is performed. The resistance was measured. The case where the conduction resistance was 30 Ω or less was evaluated as “〇”, and the case where the conduction resistance exceeded 30 Ω was evaluated as “X”.

[0081] [Insulation reliability]

For each of the electric devices 1, the insulation resistance between the adjacent connection terminals 52 of the same adherend was measured. Insulation resistance is "〇" the case of more than 1 Χ 10 ⁸ Ω, was evaluated in the case of less than 1 10 ⁸ 0 as "".

[0082] The results of these evaluation tests are shown in Table 1 above. As is clear from Table 1 above, the minimum viscosity of the first resin layer is lOOOPa · s or more and 300,000 Pa · s or less, and the film thickness of the second resin layer is equal to that of the first and third resin layers. In the electric device 1 of Example 19, which had a greater force than the film thickness, the number of conductive particles caught on the bumps was large, and high evaluation results were obtained in both conduction reliability and insulation reliability.

On the other hand, in Comparative Example 1 in which the thicknesses of the first and second resin layers were the same, the conduction reliability was excellent, but the insulation reliability was low. In Comparative Examples 2 and 3, in which the thickness of the resin layer was equal to or larger than that of the second resin layer, the conduction reliability was low. Therefore, when the thickness of the first resin layer is smaller than the thickness of the second resin layer, the conduction of the electric device is prevented. It can be seen that the reliability is increased and the insulation reliability of the electric device is increased when the thickness of the third resin layer is smaller than the second resin layer.

[0084] Further, as is apparent from Comparative Example 4, the minimum viscosity of the first resin layer is as small as 150 Pa's. The minimum viscosity of the second and third resin layers is smaller than that of the first resin layer. When the conductive particle density was also large, the conduction reliability was not improved even if the density of the conductive particles was increased as in Comparative Example 5 where the communication reliability was low.

From the results of Comparative Examples 4 and 5, in order to obtain a high conduction reliability and an electric device, the viscosity of the first resin layer is set to be lower than the minimum viscosity of the second and third resin layers. It is also found that the value needs to be larger than 100 OPa's. In Comparative Example 6, in which the first resin layer was formed using the first adhesive containing no curing agent, the evaluation result of the conduction reliability was poor.

[0086] When the difference between the minimum viscosities of resin layers adjacent to each other is large, as in the case of the first resin layer and the second resin layer, and the case of the first resin layer and the third resin layer, On the other hand, the adhesive film after being cured so that the resin layers are hardly mixed with each other at the time of heating and pressing does not become a continuous cured product. Therefore, in Comparative Example 6, it is presumed that the stress for attracting the electric parts of the cured adhesive film to each other was very small, and the communication conductivity was low.

[0087] On the other hand, when a curing agent for curing the thermosetting resin is added to the first resin layer as in Example 119 above, the conductive resin particles around the conductive particles are The first adhesive cures and shrinks when heated. In other words, since the curing shrinkage occurs around the conductive particles sandwiched between the connection terminals of the electric component, a stress that attracts the electric components is generated, so that the difference in minimum viscosity between the resin layers adjacent to each other is reduced. Even if it is large, it is assumed that the conduction reliability has increased.

Although the case where the second and third resin layers 20 and 25 do not contain conductive particles has been described above, the present invention is not limited to this. If the density of the conductive particles is lower than the density of the conductive particles, the second and third resin layers 20 and 25 may contain conductive particles.

When the thickness of the first resin layer 10 is reduced to 1Z2 times or more and 2 times or less the average particle diameter of the conductive particles 12, the surface force of the first resin layer 10 is also reduced. Part of conductive particles 12 protrude The second and third resin layers 20 and 25 may sink into the second and third resin layers 20 and 25, however, unless the second and third resin layers 20 and 25 contain conductive particles. The conductive particle density of the resin layers 20 and 25 can be smaller than the conductive particle density of the first resin layer 10.

The first and second adherends are not limited to the circuit board 40 and the semiconductor element 50. Examples of the adherend include a flexible wiring board in which a wiring film is formed on a resin film, and a resistor. Various elements such as an element and a liquid crystal display element can be used.

[0091] The types of the first to third thermosetting resins are not particularly limited, and various types such as epoxy resins, melamine resins, acrylic resins, phenol resins, and urea resins can be used.

[0092] The type of the first to third curing agents is not particularly limited, and various types can be used according to the types of the first to third thermosetting resins. For example, when an epoxy resin is used as the thermosetting resin, an imidazole-based curing agent, a polyamine-based curing agent, an acid anhydride, an isocyanate-based curing agent, an organic acid, a tertiary amine, or the like can be used. Considering the preservability of the adhesive film, it is preferable to use a latent curing agent which does not cure the thermosetting resin at room temperature but accelerates the curing reaction by heating. As the latent curing agent, those obtained by encapsulating the above-mentioned hardener and block isocyanate can be used.

[0093] The case where the filler is added only to the first resin layer 10 has been described above. However, the present invention is not limited to this, and the second and third resin layers 20 and 25 may be provided with a filler. It is also possible to add them, and by changing the type, average particle diameter and blending amount of the filler used for the second and third resin layers 20 and 30, the minimum of the second and third resin layers 20 and 25 can be added. The viscosity can be made lower than the minimum viscosity of the first resin layer 10.

[0094] As the filler to be added to the first to third resin layers, it is preferable to use an insulating one. The type of the filler is not particularly limited. In addition to diacid silicate, inorganic fillers such as talc, titanium oxide, calcium carbonate, magnesium oxide, oxidized zinc, etc., and organic fillers such as resin particles, etc. Can be used. When the average particle size of the filler is equal to or less than the average particle size of the conductive particles, and more preferably 1 μm or less, the conduction reliability between the connection terminals increases. Further, besides the filler, additives such as an antioxidant, a coloring agent, and a silane coupling agent can be added to each resin layer. [0095] As described above, in addition to the resin particles whose surfaces are covered with the conductive layer, various kinds of conductive particles such as nickel particles, silver powder, and carbon particles may be used. Can be done. Also, a mixture of two or more types of conductive particles can be used.

[0096] Further, according to the present invention, since the conductive particles are unlikely to flow between the connection terminals 52, it is possible to obtain the electric device 1 having no insulating coating and having high connection reliability even if conductive particles are used. I can do it.

[0097] Although the case where the third resin layer 25 is formed directly on the surface of the first resin layer 10 has been described above, the present invention is not limited to this. After forming the second resin layer on another release film, the third resin layer 25 and the first resin layer 10 can be bonded together.

[0098] The case where a resin layer (second resin layer 20) thicker than the first resin layer 10 is formed on the surface of the first resin layer 10 is described above. However, the present invention is not limited to this. After forming a resin layer (third resin layer 25) thinner than the first resin layer 10 on the surface of the first resin layer 10, Then, the first release film 31 is peeled off from the first resin layer 10, and the exposed surface of the first resin layer 10 is coated with a resin layer having a thickness larger than that of the first resin layer 10 (the second resin layer). A second resin layer 20) may be formed.

[0099] As the first to third release films 31 to 33, it is preferable to use a resin film whose surface (release surface) is surface-treated. As a surface treatment method, for example, there is a method of forming another resin film having low adhesiveness on the surface of the resin film.

[0100] The method of applying the first to third adhesives is not limited to the case of using a roll coater, and various methods such as a dip coating method, a knife coater method, and offset printing can be used.

[0101] The above is the description of the adhesive film with the release film in which the release films are attached to both surfaces of the adhesive film 4, respectively. The present invention is not limited to this. For example, if the surface of the second release film 21 opposite to the surface on which the second resin layer 20 is disposed is subjected to surface treatment to form a release surface, the third release film 21 Even if the adhesive film 4 is wound up without sticking, the third resin layer 25 does not adhere to the second release film 32.

Claims

The scope of the claims

[1] a first resin layer, a second resin layer disposed on the first resin layer,

A third resin layer disposed on a surface of the first resin layer opposite to the second resin layer,

The first resin layer has an insulating binder and conductive particles dispersed in the binder,

The insulating binder has a first thermosetting resin and a first curing agent that reacts with the first thermosetting resin by heating to cure the first thermosetting resin. Then, the second resin layer reacts with the insulating second thermosetting resin and the second thermosetting resin by heating to cure the second thermosetting resin. A second curing agent, wherein the third resin layer reacts with the third thermosetting resin by heating and reacts with the third thermosetting resin to form the third thermosetting resin. A third curing agent for curing the fat, disposed between a first adherend having a first connection terminal and a second adherend having a second connection terminal When the first and third resin layers are heated to a predetermined connection temperature or higher, the conductive particles are sandwiched between the first and second connection terminals. First An adhesive film configured such that the third thermosetting resin reacts with the first and third curing agents, respectively, to be cured, and the first and second adherends are connected; hand,

The first resin layer has a minimum viscosity of lOOOPa • s or more and lOOOOOOPa · s or less in a temperature range lower than the connection temperature,

The second resin layer has a minimum viscosity in a temperature range lower than the connection temperature lower than a minimum viscosity of the first resin layer in a temperature range lower than the connection temperature; The adhesive film, wherein the thickness of the resin layer is larger than the thicknesses of the first and third resin layers.

[2] The second resin layer has a minimum viscosity in a temperature range lower than the connection temperature of 1Z10 or less of a minimum viscosity of the first resin layer in a temperature range lower than the connection temperature. The adhesive film according to claim 1, wherein

[3] The thickness of the first resin layer is 1Z2 times or more and 2 times or less the average particle size of the conductive particles. 3. The adhesive film according to claim 1, wherein

4. The adhesive according to claim 1, wherein the conductive resin density of the first resin layer is higher than the conductive particle density of the second resin layer. the film.

[5] The thickness of the second resin layer may be set to be equal to or smaller than the thickness of the first and second adherends. 5. The adhesive film according to claim 1, wherein the thickness of the adhesive film is larger than the thickness of the terminal.

[6] The third resin layer has a lower viscosity in the temperature range than the connection temperature! The lowest viscosity in the temperature range is lower than the minimum viscosity in the temperature range lower than the connection temperature of the first resin layer. The adhesive film according to any one of claims 1 to 5, which is provided.

[7] The third resin layer has a minimum viscosity in a temperature range lower than the connection temperature of 1Zio or less of a minimum viscosity of the first resin layer in a temperature range lower than the connection temperature. 7. The adhesive film according to claim 6, wherein:

8. The adhesive film according to claim 1, wherein the thickness of the third resin layer is smaller than the thickness of the first resin layer.

[9] A method for producing an adhesive film for producing an adhesive film having a release film attached to at least one surface thereof,

A first release film,

A first resin layer disposed on the surface of the first release film,

A second resin layer disposed on the surface of the first resin layer,

Having a second release film disposed on the surface of the second resin layer,

The laminated body, wherein the minimum viscosity in a temperature range lower than the connection temperature of the first resin layer is set higher than the minimum viscosity in a temperature range lower than the connection temperature of the second resin layer, Peeling a first release film from the first resin layer to expose a surface of the first resin layer,

A method for producing an adhesive film, wherein a liquid adhesive is applied to the exposed surface of the first resin layer and dried to form a third resin layer.

[10] In the production of the laminate, a liquid adhesive is applied to the surface of the first release film and dried to form the first resin layer, After applying a liquid adhesive on the surface of the first resin layer and drying to form the second resin layer, the second release film is attached to the surface of the second resin layer. The method for producing an adhesive film according to claim 9.

The production of the laminate is performed by applying a liquid adhesive on the surfaces of the first and second release films and drying the first and second resin layers to form the first and second resin layers. 10. The method for producing an adhesive film according to claim 9, wherein the surface of the layer and the surface of the second resin layer are adhered to each other.