JP5143329B2 - Manufacturing method of circuit connection body - Google Patents

Description

【表２】

【００２１】
実施例１〜３は、いずれも接続抵抗、接着力、絶縁性ともに良好な結果であり、良好な接続性を示した。これに対して、Ｔ／Ｒが４を超えた比較例１、６においては、絶縁性に劣った。また、導電性粒子径が５μｍを超えた比較例２、４、５は、接着力や絶縁性に劣った。
【００２２】
【発明の効果】
本発明による接続方法を用いると、導電性粒子不足による接続不具合や隣接する電極間での短絡などの電気的特性不足の問題を一気に解決することができ、回路接続用接着剤の性能を飛躍的に向上させることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of making a circuit connection member using a circuit connection adhesive.
[0002]
[Prior art]
Conventionally, anisotropic conductive material in which conductive particles are dispersed in an adhesive is used for connection between a liquid crystal display and TCP (tape carrier package) or FPC (flexible printed wiring board) and TCP, and between FPC and printed wiring board. Adhesive is used. Recently, even when a semiconductor silicon chip is mounted on a substrate, so-called flip chip mounting in which the semiconductor silicon chip is directly mounted on the substrate face down is performed instead of the conventional wire bond. Adhesives have been applied (Japanese Patent Laid-Open Nos. 59-120436, 60-191228, 1-251787, and 7-90237).
[0003]
[Problems to be solved by the invention]
However, in recent years, with the downsizing and thinning of electronic devices, the density of circuits has been increasing, and the distance between electrodes and the width of electrodes have become very narrow. In addition, the circuit itself is becoming thinner. Therefore, if the conventional anisotropic conductive adhesive is used as it is, a connection failure due to lack of conductive particles occurs, or if a large amount of conductive particles are added to compensate for the lack of conductive particles, the connection failure is solved, but the adjacent electrode There was a problem such as short-circuiting. The present invention is a circuit connection using an adhesive for circuit connection that does not cause the above-mentioned connection failure and can be connected well in response to a high-density circuit without causing a short circuit between adjacent electrodes. A method for producing a body is provided.
[0004]
[Means for Solving the Problems]
( I ) The present invention is such that only the circuit connecting adhesive is interposed between the substrates having the opposite circuit electrodes, and the circuit connecting adhesive between the electrodes of the substrates having the opposite circuit electrodes by pressing or heating is used. A method for producing a circuit connection body that is electrically connected by conductive particles contained therein , wherein the adhesive for circuit connection contains conductive particles, an epoxy resin, a film forming material, and a curing agent, and , the thickness of the circuit connecting adhesive T ([mu] m), the average particle diameter R of the conductive particles ([mu] m), and electrically relationship of the connected opposing sum of electrode height of the circuit electrodes H ([mu] m) the following formula (1), meets the (2) and (3), the film-forming material is polyvinyl butyral resins, polyvinyl formal resins, polyester resins, polyamide resins, polyimide resins, xylene resins, phenoxy resins, polyurethane Including resins, urea resins, and one or more polymeric components selected from the group consisting of acrylic rubber, a method for manufacturing a circuit connection member.
1.5 ≦ T / R ≦ 2.5 (1)
1 ≦ R ≦ 5 (2)
0.2 ≧ H / R (3)
Moreover, ( ii ) this invention is a manufacturing method of the circuit connection body as described in said ( i ) whose adhesive agent for circuit connection is a film form. Moreover, ( iii ) this invention is a manufacturing method of the circuit connection body as described in said ( i ) or said ( ii ) by which the surface of electroconductive particle is coated with the insulating substance.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
When the connection method according to the present invention is used, it is possible to solve the problem of insufficient electrical characteristics such as connection failure due to insufficient conductive particles and short circuit between adjacent electrodes at a stretch, and the performance of the adhesive for circuit connection is greatly improved. Can be improved.
[0006]
As an adhesive for circuit connection used in the present invention, thermoplastic resins such as acrylic rubber, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, epoxy resin, (meth) acrylic resin, Although thermosetting resins such as maleimide resin, citraconic imide resin, nadiimide resin, and phenol resin are used, it is preferable to use a thermosetting resin in terms of heat resistance and reliability.
[0007]
A thermosetting adhesive is suitably applied as the circuit connecting adhesive used in the present invention. As the thermosetting component, an epoxy resin, a (meth) acrylic resin, a maleimide resin or the like can be used. In addition, in order to impart film formability, adhesiveness, and stress relaxation during curing to the circuit connection adhesive of the present invention, polyvinyl butyral resin, polyvinyl formal resin, polyester resin, polyamide resin, polyimide resin, xylene resin Polymer components such as phenoxy resin, polyurethane resin, urea resin, and acrylic rubber can also be used. These polymer components preferably have a molecular weight of 10,000 to 10,000,000, and preferably have a functional group such as a carboxyl group, a hydroxyl group, and an epoxy group, because the adhesion is improved. These resins may be modified with a polymerizable functional group such as a radical polymerizable functional group or an epoxy group. In this case, heat resistance is improved, which is preferable. In addition, an adhesive that is cured by heating at 120 to 140 ° C. for about 15 seconds and an adhesive that is cured by light irradiation are preferable because thermal damage can be reduced.
Further, the adhesive for circuit connection can be applied even in a liquid state, but in the case of a film, it is suitable in terms of workability.
[0008]
Examples of the conductive particles contained in the circuit connection adhesive used in the present invention include metal particles such as Au, Ag, Ni, Cu, and solder, carbon, or non-conductive particles such as glass, ceramic, and plastic. Particles coated with noble metals such as platinum are used. In the case of metal particles, those coated with noble metals are preferred in order to suppress surface oxidation. Among the above conductive particles, particles coated with Au, Ag, etc. using plastic as a core and heat-melted metal particles are deformed by heating and pressurization at the time of connection, and absorb the variation in the height of the circuit electrode, and the contact area This increases the reliability and improves the reliability. In particular, particles coated with Au, Ag, etc. using a plastic core are preferable because there are few short circuits between circuit electrodes. If the thickness of the noble metal coating layer is 100 mm or more, preferably 300 mm or more, good connection can be obtained. Further, it is preferable to coat the conductive particles with an insulating substance since the occurrence of a short circuit between adjacent electrodes is suppressed. The coating thickness is preferably as thin as a surface treatment of submicron or less in order to connect circuit electrodes and to prevent a short circuit between adjacent electrodes. The conductive particles are appropriately blended depending on the application in the range of 0.1 to 30% by volume, more preferably 0.1 to 10% by volume with respect to 100 volumes of the adhesive component.
[0009]
A filler, a softening agent, an accelerator, an anti-aging agent, a colorant, a flame retardant, and a coupling agent may be appropriately added to the circuit connection adhesive of the present invention.
[0010]
The substrate used in the present invention is not particularly limited as long as an electrode that requires electrical connection is formed, but glass or plastic on which an electrode is formed of ITO or the like used for a liquid crystal display. There are a substrate, a printed wiring board, a flexible wiring board, a ceramic wiring board, a semiconductor silicon chip, a TCP, a two-layer FPC, etc., which are used in combination as necessary. At this time, the sum H of the electrode heights of the opposing circuit electrodes that require electrical connection, the average particle diameter R of the conductive particles contained in the circuit connection adhesive used, and the thickness T of the circuit connection adhesive The relationship needs to satisfy the following equations (1) and (2).
1.5 ≦ T / R ≦ 2.5 (1)
1 ≦ R ≦ 5 (2)
In the present invention, an average particle diameter R of conductive particles contained in the adhesive for circuit connection is obtained in order to obtain a good connection corresponding to the increase in circuit density without causing a short circuit between adjacent electrodes. There Ru using the 1~5μm and a small-diameter particles. And, the satisfying electrically average particle diameter R is following formulas conductive particles contained in the electrode height sum H and circuit connection adhesive of the connected opposing circuit electrodes (3).
0.2 ≧ H / R (3)
When the average particle diameter R of the conductive particles is less than 1 μm, it is difficult to produce the conductive particles, or short circuit between adjacent electrodes is likely to occur due to aggregation of the conductive particles. Further, when the average particle diameter R of the conductive particles is 5 μm or more, it becomes as large as the electrode width due to circuit densification, and a short circuit between the electrodes is likely to occur. The average particle diameter is preferably closer to monodispersion in order to ensure uniform connection of circuit electrodes, and more preferably within a range of 1 μm from the average particle diameter, and more preferably within a range of 0.5 μm. The thickness T of the adhesive for circuit connection of Formula (2) to Formula (1) is in the range of 1.5 to 12.5 μm . If the thickness T of the circuit connecting adhesive is less than 0.25 μm, it is difficult to manufacture, or the adhesive is likely to be insufficient at the time of connection, resulting in poor connection reliability. On the other hand, if it exceeds 20 μm, most of the adhesive must be flowed. At this time, a short circuit between the electrodes due to the flow of the conductive particles tends to occur. If the total electrode height H of the circuit electrode exceeds 5 μm, a circuit electrode having a fine circuit width cannot be formed, and the height of the electrode increases, so that most of the adhesive must flow. In this case, a short circuit between the electrodes due to the flow of the conductive particles is likely to occur. Because of these, the electrode height of the sum H of the circuit electrodes, electrostatic inter-electrode can sufficiently fill, preferably as long as it is a thickness that does not flow as possible adhesive.
[0011]
As a method for producing an adhesive for circuit connection, production by a known general method can be applied. However, after a film composed only of an adhesive is produced, a conductive particle layer uniformly dispersed therein is transferred and formed. In this case, it is preferable to easily control the thickness of the adhesive.
[0012]
There are no particular restrictions on the conditions for electrically connecting the electrodes of the substrate having circuit electrodes, but the connection temperature is 90 to 250 ° C., the connection time is 1 second to 1 minute, and the connection pressure is in the range of 1 to 5 MPa. It is appropriately selected depending on the intended use, adhesive, and substrate, and post-curing may be performed as necessary. The connection is performed by heating, pressurization, or heating and pressurization, but energy other than heat, for example, light, ultrasonic waves, electromagnetic waves, or the like may be used as necessary.
[0013]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not restrict | limited to this Example.
(Production of adhesive)
Using the simple coating machine (manufactured by Tester Sangyo Co., Ltd.), the following composition was applied to a PET (polyethylene terephthalate) film having a surface treated on one side having a thickness of 50 μm. An adhesive film for circuit connection was produced by hot air drying.
[0014]
Example 1
(Production of adhesive for circuit connection)
As a thermosetting component, a bisphenol A type epoxy resin (Epicote 828, product name manufactured by Yuka Shell Epoxy Co., Ltd.) was used. Acrylic rubber (weight average molecular weight of about 800,000, Tg; −22 ° C., containing epoxy group) and phenoxy resin (PKHC; trade name of Union Carbide, weight average molecular weight 45000) were used as the film forming material. As the curing agent, a microcapsule type curing agent (HX3941HP, trade name, manufactured by Asahi Kasei Epoxy Corporation) was used. As a conductive particle, a nickel layer having a thickness of 0.2 μm is provided on the surface of a particle having polystyrene as a core, and a gold layer having a thickness of 0.04 μm is provided outside the nickel layer. Conductive particles were prepared, and the surface was coated with 0.01 μm of polyvinyl alcohol.
It is blended so as to be 30 g of acrylic rubber, 10 g of phenoxy resin, 10 g of bisphenol A type epoxy resin, 50 g of microcapsule type curing agent, 1 g of silane coupling agent (SH6040, trade name of Toray Dow Silicone Co., Ltd.) Further, 3% by volume of conductive particles were mixed and dispersed to obtain a circuit connecting material having a circuit connecting adhesive thickness (T) of 6 μm.
[0015]
(Example 2)
In the same manner as in Example 1, 1% by volume of conductive particles were mixed and dispersed to obtain a circuit connecting material having an adhesive layer thickness of 6 μm.
[0016]
(Example 3)
2% by volume of conductive particles having an average particle diameter of 2 μm prepared in the same manner as in Example 1 were mixed and dispersed, and a circuit connection material having an adhesive layer thickness of 5 μm was obtained in the same manner as in Example 1.
[0017]
(Comparative Example 1)
In the same manner as in Example 1, a circuit connecting material having an adhesive thickness of 25 μm was obtained.
(Comparative Example 2)
Although it was the same as that of Example 1, the circuit connection material whose thickness of an adhesive agent is 10 micrometers was obtained using the electroconductive particle with an average particle diameter of 6 micrometers.
(Comparative Example 3)
In the same manner as in Example 1, a circuit connecting material having an adhesive thickness of 15 μm was obtained.
(Comparative Example 4)
Although it was the same as that of Example 1, the circuit connection material whose thickness of an adhesive agent is 15 micrometers was obtained using the electroconductive particle with an average particle diameter of 6 micrometers.
(Comparative Example 5)
Although similar to Example 1, conductive particles having an average particle diameter of 6 μm were used to obtain a circuit connecting material having an adhesive thickness of 22 μm.
(Comparative Example 6)
In the same manner as in Example 1, a circuit connecting material having an adhesive thickness of 22 μm was obtained.
[0018]
(Production of connected body)
The circuit connection materials (adhesives for circuit connection) of Examples 1 to 3 and Comparative Examples 1, 2 and 5 were slit to 1.5 mm width, and 0.2 μm thick ITO was formed on the entire surface as electrodes. Temporary connection was performed on a glass substrate under the conditions of 80 ° C., 5 seconds, and 1 MPa. Thereafter, the PET base material is peeled off, and the electrodes of the ITO electrode and the glass substrate (ITO 500 μm, ITO thickness 0.2 μm) on which the ITO pattern is formed are aligned, and the conditions are 180 ° C., 15 seconds, and 3 MPa. This connection was made.
In addition, the circuit connection material (adhesive for circuit connection) of Comparative Examples 3, 4, and 6 was slit to a width of 1.5 mm, and on a glass substrate on which ITO having a thickness of 0.2 μm was formed as an electrode on the entire surface. Temporary connection was performed under the conditions of 5 ° C., 1 MPa. Then, the PET substrate was peeled off, and the ITO electrode and the two-layer FPC (pitch 500 μm, the circuit was produced by etching, the electrode heights were 12 μm (Comparative Examples 3 and 4), 6 μm (Comparative Example 6), and the two layers were The electrodes of a copper foil and a polyimide film (a two-layer configuration of a copper foil and a polyimide film) that form a circuit that does not use an adhesive for laminating the copper foil and the base film were aligned, and main connection was performed at 180 ° C., 15 seconds, and 3 MPa.
[0019]
(Characteristic evaluation method)
Connection resistance: Resistance between adjacent circuits was measured at a constant current of 1 mA using a multimeter TR6848 manufactured by Advantest Corporation.
Adhesive strength: Measured at 90 ° peel according to JIS Z-0237.
Insulation: In Examples 1 to 3 and Comparative Examples 1, 2, and 5, the above circuit connection material was slit into a width of 1.5 mm, and on a glass substrate on which ITO (0.2 μm) was formed as an electrode, Temporary connection was performed at 80 ° C., 5 seconds, and 1 MPa. After that, the PET substrate was peeled off, and the ITO electrode formed with an electrode of ITO and a pitch of 50 μm, 100 lines and an electrode height of 0.2 μm was aligned, and main connection was performed at 180 ° C. for 15 seconds at 3 MPa. . Evaluation was performed using the number of short-circuited insulation evaluations after 30 connection bodies were prepared. Comparative Examples 3, 4, and 6 are two-layer FPC electrodes in which ITO (0.2 μm), pitch 50 μm, 100 lines, and electrode heights of 12 μm (Comparative Examples 3 and 4) and 6 μm (Comparative Example 6) are formed. The main connection was performed at 180 ° C. for 15 seconds at 3 MPa. Evaluation was performed using the number of short-circuited insulation evaluations after 30 connection bodies were prepared.
Reliability evaluation: With respect to the connection resistance, a high-temperature and high-humidity test was performed under the conditions of 80 ° C. and 95% RH, and the value was measured after 240 hours.
The measurement results are shown in Tables 1 and 2 .
[0020]
[Table 1]

[Table 2]

[0021]
In Examples 1 to 3, all of the connection resistance, adhesive force, and insulation were good results, and good connectivity was shown. On the other hand, in Comparative Examples 1 and 6 in which T / R exceeded 4, the insulation was inferior. Moreover, Comparative Examples 2, 4, and 5 in which the conductive particle diameter exceeded 5 μm were inferior in adhesive strength and insulation.
[0022]
【Effect of the invention】
By using the connection method according to the present invention, it is possible to solve the problem of insufficient electrical characteristics such as connection failure due to insufficient conductive particles and short circuit between adjacent electrodes at once, and the performance of the adhesive for circuit connection is drastically improved. Can be improved.

Claims (3)

By interposing only the adhesive for circuit connection between the substrates having circuit electrodes facing each other, the conductive particles contained in the adhesive for circuit connection between the electrodes of the substrates having circuit electrodes facing each other by pressure or heating . A method for producing a circuit connection body to be electrically connected,
The adhesive for circuit connection contains the conductive particles, an epoxy resin, a film forming material, and a curing agent, and has a thickness T (μm) of the adhesive for circuit connection , and the conductive particles. the average particle diameter R ([mu] m), and electrically connected to opposing the circuit electrodes of the electrode height sum H ([mu] m) of the relationship following formula is (1), (2) and (3) Meet,
The film forming material includes at least one polymer component selected from the group consisting of polyvinyl butyral resin, polyvinyl formal resin, polyester resin, polyamide resin, polyimide resin, xylene resin, phenoxy resin, polyurethane resin, urea resin, and acrylic rubber. A method for manufacturing a circuit connection body.
1.5 ≦ T / R ≦ 2.5 (1)
1 ≦ R ≦ 5 (2)
0.2 ≧ H / R (3) The method for producing a circuit connection body according to claim 1, wherein the circuit connection adhesive is in a film form. The method for manufacturing a circuit connector according to claim 1, wherein the surface of the conductive particles is coated with an insulating material.