JPH11148063A - Production of adhesive for connecting circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an adhesive for connecting a circuit, providing the connecting part with minimized bubbles, having small change of viscosity and excellent in connecting reliability. SOLUTION: A filler is previously homogeneously dispersed in or kneaded with a liquid components of an adhesive to minimize the mixing of bubbles at the connecting part, and a potential hardener is mixed with the dispersed or kneaded product and thereafter stirring and degassing the obtained mixture to provide the objective adhesive for connecting the circuit having small change of viscosity and excellent in connection reliability in the method for producing the adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a circuit connecting adhesive used for connecting circuit boards to each other or to an IC chip or an electronic component.

[0002]

2. Description of the Related Art As a method for electrically connecting electronic components to each other, a wire bonding method and the like are known. However, as electronic components have become smaller and more dense, a flip-chip mounting method has recently attracted attention. Is coming. One of them is a connection method using an anisotropic conductive adhesive film. An anisotropic conductive adhesive film is made of an adhesive containing a predetermined amount of conductive fine particles such as metal particles. The anisotropic conductive adhesive film is provided between an electronic component and an electrode or a circuit, and is pressed or heated. By applying the pressing means, the two electrodes are electrically connected to each other, and at the same time, the insulation between the adjacent electrodes is provided, and the electronic component and the circuit are bonded and fixed. When a plurality of semiconductor chips having different sizes are mounted on a substrate using an anisotropic conductive adhesive film, it is necessary to prepare at least different types of anisotropic conductive adhesive films. This problem is solved by filling a liquid anisotropic conductive adhesive in a syringe-shaped container. In this case, only one kind of anisotropic conductive adhesive is required, and it is only necessary to exchange the nozzle at the tip or change the pattern to be applied according to the semiconductor chip to be printed or connected.

[0003]

When an anisotropic conductive adhesive is used, it is possible to selectively apply it on an electrode by using a mask. Sex is also important. To exhibit excellent printability, the adhesive needs to have a somewhat high viscosity. In order to increase the viscosity of the adhesive, a filler such as silica is generally used as a thickener. Since the filler is a particle having a very small diameter, if handled as it is, a large amount of dust is generated during the production of the adhesive, which not only impairs the worker's health but also increases the measurement error at the time of weighing. If the fine particles such as filler are not sufficiently kneaded into the adhesive, bubbles on the surface of the fine particles remain in the adhesive as it is, which adversely affects the connection reliability after connecting the electronic component. The present invention minimizes the scattering of fillers, minimizes bubbles in the connection area, and efficiently kneads and removes the adhesive material for circuit connection with excellent connection reliability after connecting electronic components. A method for producing an adhesive is provided.

[0004]

SUMMARY OF THE INVENTION A method for producing a circuit connection adhesive according to the present invention is a method for producing a circuit connection adhesive comprising kneading a thickener, a latent curing agent, a liquid epoxy resin, and conductive fine particles as essential components. A production method characterized in that a thickener is previously dispersed and kneaded in a liquid component, and conductive fine particles are previously dispersed and kneaded in a liquid component. Further, the method for producing a circuit connection adhesive of the present invention is a method for producing a circuit connection adhesive in which a thickener, a latent curing agent, a liquid epoxy resin, and conductive fine particles are kneaded as essential components. It is characterized in that a viscous agent or conductive fine particles are previously dispersed and kneaded in a liquid component. Further, the method for producing a circuit connection adhesive of the present invention is a method for producing a circuit connection adhesive in which a thickener, a latent curing agent, a liquid epoxy resin, and conductive fine particles are kneaded as essential components. It is characterized in that the viscosity agent and the conductive fine particles are previously dispersed and kneaded in the liquid component. Further, the method for producing a circuit connection adhesive of the present invention is a method for producing a circuit connection adhesive in which a thickener, a latent curing agent, a liquid epoxy resin, and conductive fine particles are kneaded as essential components. It is characterized in that components other than the ionic curing agent are dispersed and kneaded in advance. Further, the method for producing a circuit connection adhesive of the present invention is a method for producing a circuit connection adhesive in which a thickener, a latent curing agent, a liquid epoxy resin, and conductive fine particles are kneaded as essential components. It is characterized in that the thickener is dispersed and kneaded in advance in a liquid component excluding the latent curing agent, and then the kneaded product and other components including the latent curing agent are defoamed while being mixed and stirred. The method for producing a circuit connection adhesive of the present invention is a method for producing a circuit connection adhesive in which a thickener, a latent curing agent, a liquid epoxy resin, and conductive fine particles are kneaded as essential components.
After previously dispersing and kneading the thickener in the liquid component excluding the latent curing agent, in the step of defoaming while mixing and stirring the kneaded product and other components including the latent curing agent, The container is defoamed while mixing and stirring at the same time by the simultaneous rotation of the rotation centered on the center of the bottom of the container and the rotation centered on the same plane as the bottom of the container. It is characterized by obtaining.

That is, as a method for solving the above-mentioned problem, there is a method in which a filler, which is one of the thickeners as a powder component, is uniformly dispersed or kneaded in a liquid component of the adhesive before the production of the adhesive. By providing a step (step A) of uniformly dispersing or kneading the filler in the liquid component of the adhesive in advance separately from the step of manufacturing the adhesive (step B), the step A and the step B can be performed at different times. It can be done at the place. FIG. 1 shows an example of the operation in the step A. A container 2 (for example, a mortar) used for kneading, a filler 3, a liquid component 4, and a balance 5 are put in a transparent closed container 1, and an operator 6 uniformly disperses or kneads through a glove 7 provided in the closed container 1. I do. As described above, by performing the operation of the step A in a transparent closed container, not only the health of the worker can be protected, but also the scattering of dust can be minimized, and the measurement error at the time of weighing can be minimized. Can be minimized. In the operation of the step A, conductive fine particles may be uniformly dispersed or kneaded in advance in the liquid component of the adhesive in addition to a thickener such as a filler. In the present invention, the liquid component includes additives such as a coupling agent in addition to the liquid epoxy resin.
Dispersion and kneading of the adhesive material are performed by rotating the container containing the kneaded material around the center of the bottom of the container as an axis, and rotating the container at the same plane as the bottom of the container and around a point outside the bottom of the container as the center axis. So-called planetary-type mixer (hereinafter referred to as
Degas with mixing and stirring using a “planetary mixer”. A mill or a three-roll mill may be used, but for the dispersion and kneading in the step B including the latent curing agent in the kneaded material, a planetary mixer that does not mechanically destroy the latent curing agent is preferable. . Therefore, in the above-mentioned step A, fine particles such as a thickener are dispersed and kneaded in a resin using a three roll or the like, so that the fine particles are blended well.
In the process, it can be dispersed and kneaded together with a latent curing agent using a planetary mixer. FIG. 2 is an explanatory view of the rotating section of the planetary mixer. The container 8 containing the kneaded material is rotated about the center 9 of the bottom surface of the container as an axis, and the rotating body 11 is coplanar with the bottom surface of the container and has a center 10 at a point 10 outside the bottom surface of the container.
Defoaming while mixing and stirring by the simultaneous use of the rotating motions. FIG. 3 is a cross-sectional view of a rotating part of the planetary mixer. Between the bottom surface of the container 8 and the bottom surface of the rotating body 11 (θ <0 <
θ).

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION As the adhesive used in the production method of the present invention, for example, the viscosity of the adhesive is 30 measured by an EHD type viscometer using a 3 ° cone.
° C, when the cone rotation speed is 0.5 rpm, 25-1,
000 Pa · s, as an adhesive capable of obtaining good moisture resistance after connection, epoxy resin and imidazole, hydrazide, boron trifluoride-amine complex, sulfonium salt, amine imide, polyamine salt, dicyandiamide, etc. And a mixture of a latent curing agent of the formula (1) and acrylic rubber fine particles such that the viscosity of the adhesive is 25 to 1,000 Pa · s under the above measurement conditions. The viscosity of the adhesive at 30 ° C. can be measured using, for example, an EHD type viscometer manufactured by Tokyo Keiki Co., Ltd. The adhesive produced in the production method of the present invention contains a liquid epoxy resin, a latent curing agent, a thickener, and conductive fine particles.

The thickener used in the present invention has a purity of 80
% Or more of SiO _2, Al ₂ O ₂ or TiO ₂ , preferably having a particle size of 5 μm or less.
The following is more preferred. Further, the surface of the fine particles may be surface-treated with an organic substance such as dimethyl silicone oil, octylsilane, or trimethylsilyl group.

The liquid epoxy resin used in the present invention includes epichlorohydrin and bisphenol A, F, AD
Bisphenol-type epoxy resin derived from such as, epoxy novolak resin derived from epichlorohydrin and phenol novolak or cresol novolac, naphthalene-based epoxy resin having a skeleton containing a naphthalene ring, glycidylamine, glycidyl ether, biphenyl, alicyclic, etc. It is possible to use various epoxy compounds or the like having two or more glycidyl groups in one molecule, alone or as a mixture of two or more. For these epoxy resins, it is preferable to use high-purity products in which impurity ions (Na +, Cl −, etc.), hydrolyzable chlorine and the like are reduced to 300 ppm or less for preventing electromigration.

The adhesive produced in the production method of the present invention may contain an epoxy resin in which fine particles of acrylic rubber are dispersed for improving moisture resistance and heat resistance, and the rubber particles have a particle size of 0.02 to 1 μm. Having a diameter of, for example, uniformly dispersed as primary particles in an epoxy resin, and is preferably obtained by directly mixing a rubber emulsion with the epoxy resin and dehydrating the epoxy resin. The rubber emulsion is an aqueous dispersion of rubber obtained from emulsion polymerization, suspension polymerization or solution polymerization, and examples thereof include acrylic emulsion, SBR, NBR and the like.
An acrylic rubber emulsion having a glass transition temperature of room temperature or lower, which is obtained by emulsion polymerization of a (meth) acrylic acid ester-based monomer, is preferably used. The particle size of the rubber particles is 0.02 to 1 μm
However, the thickness is preferably 0.1 to 0.6 μm from the viewpoint of cured physical properties and workability when formed into an epoxy resin composition. Further, the acrylic rubber particles of the present invention may be particles having a cross-sectional structure having a plurality of layer structures, such as core-shell acrylic particles. The method for producing the core-shell acrylic particles is not particularly limited, but is usually produced by continuous multi-stage seed emulsion polymerization of at least two stages. First, the first stage has a glass transition temperature of −20 ° C.
The combination of the first monomer having the composition to form the following copolymer, the second monomer and the crosslinkable monomer, in the presence of an emulsifier, a peroxide initiator as a polymerization initiator And emulsion polymerization using a radical polymerization initiator such as a redox initiator to obtain a seed latex containing a core component. The second stage contains a core component obtained in the first stage with a combination of a third monomer and a crosslinkable monomer having a composition that forms a polymer having a glass transition temperature of 0 ° C. or higher. In addition to the seed latex, a shell component is formed by emulsion polymerization using a radical polymerization initiator such as a peroxide initiator or a redox initiator as a polymerization initiator in the presence of an emulsifier. Thus, the particle size is 0.03 μm
Core-shell acrylic fine particles of about 0.5 μm can be obtained.

The epoxy resin composition obtained by mixing and dehydrating a rubber emulsion and an epoxy resin according to the present invention is obtained by directly mixing a rubber emulsion with an epoxy resin and removing water while stirring under normal pressure or reduced pressure. Is obtained. At this time, if the treatment is further performed with a high-pressure homogenizer after removing the water, the viscosity of the epoxy resin composition is reduced, and the workability at the time of preparing the adhesive composition is improved. The amount of rubber particles dispersed in the epoxy resin composition is preferably 1 to 60 parts by weight, more preferably 100 parts by weight of the epoxy resin,
It is 2 to 30 parts by weight.

Further, in order to improve the connection reliability of electronic products connected using the adhesive manufactured by the manufacturing method of the present invention,
Various coupling agents may be added to the adhesive. As the coupling agent, besides the silane coupling agent, a titanate coupling agent or an aluminum-based coupling agent may be used depending on the use, or a mixture of these may be used. The addition amount is preferably 0.1 to 5 parts by weight.

In the adhesive manufactured by the manufacturing method of the present invention, conductive fine particles are dispersed for the purpose of positively imparting anisotropic conductivity in order to absorb height variations of chip bumps and substrate electrodes. You can also. The conductive fine particles are, for example, A
Metal particles such as u, Ag, Cu, and solder may be used, in which a conductive layer of Ni, Cu, Au, solder, or the like is provided on a polymer spherical core material such as polystyrene. Furthermore, a surface layer of Su, Au, solder, or the like can be formed on the surface of the conductive particles. The particle size needs to be smaller than the minimum distance between the electrodes on the substrate, and if there is a variation in the height of the electrodes, it is preferably larger than the variation in height, and preferably 1 to 10 μm. The amount of the conductive fine particles dispersed in the adhesive is preferably 0.1 to 20% by volume based on 100 parts by volume of the adhesive. As a circuit member to be adhered to the adhesive manufactured by the present invention, a semiconductor chip, a resistor chip,
Chip components such as capacitor chips, printed boards, and substrates such as flexible wiring boards based on polyimide or polyester are used. These circuit members are usually provided with a large number of connection terminals, and at least one set of the circuit members is arranged such that at least a part of the connection terminals provided on those circuit members are opposed to each other. An adhesive is interposed, and the connection terminals facing each other are heated and pressurized and electrically connected to each other to form a circuit board.

When at least one set of the circuit members is heated and pressurized, the connection terminals arranged opposite to each other are electrically connected by direct contact or via conductive fine particles of an anisotropic conductive adhesive. On the electrode pads of the semiconductor chip and the substrate, the bumps formed by plating and the tips of the gold wires are melted with a torch or the like to form gold balls, and the balls are pressed on the electrode pads, and then the wires are cut. A protruding electrode such as a wire bump obtained by the above method can be provided and used as a connection terminal.

As described above, the terminals of the semiconductor chip include gold,
The tip of a metal wire made of gold, aluminum, or the like is formed into a ball shape by thermal energy, and the ball is pressed onto an electrode pad of a semiconductor chip that forms a connection terminal. rear,
A bump electrode formed by cutting the metal wire, such as a ball bump, a solder ball, a molten solder molded bump, or a bump electrode formed by soldering a column can be used.

A substrate (chip mounting substrate) on which an electrode (connection terminal) corresponding to a semiconductor chip terminal is formed using an adhesive manufactured by the manufacturing method of the present invention.
Can be implemented. An electrode (connection terminal) corresponding to a semiconductor chip terminal as such a chip mounting substrate
The organic insulating substrate on which is formed is used. As the organic insulating substrate, a synthetic resin film such as a polyimide resin or a polyester resin, or a laminated substrate obtained by impregnating a glass substrate such as a glass cloth or a glass nonwoven cloth with a resin such as a polyimide resin, an epoxy resin, or a phenol resin and curing the resin. used. Further, as a chip mounting substrate, an electrode connected to the chip terminal, a surface insulating layer on which the electrode is formed, a predetermined number of insulating layers, a predetermined number of wiring layers disposed via the insulating layers, a predetermined number of wiring layers, A multilayer wiring board having a conductive hole for electrically connecting the electrode / wiring layer can be used.The predetermined number of insulating layers are made of a resin reinforced with a glass base material. Dynamic viscoelasticity meter (for example, Rheospectra DVE-4 manufactured by Rheology Co., Ltd. (tensile mode, frequency 10 Hz, heating rate 5 ° C./min.-40)
C.-250.degree. C.).
1, when the elastic modulus measured with a dynamic viscoelasticity instrument insulating layer made of resin reinforced with a glass substrate and E2, the multilayer wiring board using preferably E1 = 0.01E ² ~0.5E ² Is done. Further, in such a multilayer wiring board, the elastic modulus of the surface insulating layer measured by a dynamic viscoelasticity measuring instrument is preferably 25 ° C 100 to 10,000MP 100 ° C 10 to 1,000MP.

As such a multilayer wiring board, an insulating layer and a conductive circuit layer are alternately formed on a substrate constituted by an insulating layer using glass cloth or a wiring board having one or more conductive circuits. A build-up multilayer substrate is preferred. For the surface insulating layer, a resin film can be used,
The resin film may be a film of an epoxy resin, a polyimide resin, a polyamide imide resin, a modified polyphenylene ether resin, a phenoxy resin, an amide epoxy resin, a phenol resin, a mixture thereof, a copolymer, or the like, and a polysulfone, a polyether sulfone, or a polyether sulfone. A heat-resistant thermoplastic engineering plastic film such as ether ether ketone, wholly aromatic liquid crystal polyester, or fluorine resin can be used. A resin film containing an organic or inorganic filler can be used. As the insulating layer made of a resin reinforced with a glass base material, a prepreg obtained by impregnating a glass base material such as a glass cloth or a glass nonwoven fabric with a resin such as an epoxy resin or a phenol resin and curing the resin can be used.

As a chip mounting board, a wiring board having electrodes connected to chip terminals embedded in the surface of an insulating substrate is used. Such a wiring substrate is formed by forming a thin nickel layer on a conductive temporary substrate such as a copper foil or a stainless steel plate, applying a plating resist to a portion other than where an electrode is to be formed, and performing electrolytic copper plating to form an electrode. By pressing an insulating layer such as a polyimide film or a glass-based epoxy resin prepreg on the surface of the substrate, embedding a copper electrode in the insulating layer, and mechanically and chemically peeling and removing the conductive temporary substrate and the nickel thin layer. be able to. Also, a nickel thin layer on the conductive temporary substrate,
A copper layer is formed, an etching resist is applied to a portion where an electrode is to be formed, and an electrode is formed by etching. In such a wiring board, the repairability of the semiconductor chip is improved.

[0018]

EXAMPLES Using three rolls, a thickener (inorganic filler): liquid epoxy (bisphenol A type epoxy, epoxy equivalent 185 g / eq): liquid epoxy (bisphenol F type epoxy, epoxy equivalent 169 g / eq):
A master batch consisting of nickel particles (average particle diameter 3 μm) = 2 parts by weight: 9 parts by weight: 9 parts by weight: 13.3 parts by weight was prepared in advance, and a silane coupling agent (γ-glycidoxypropyl tri 1 part by weight of methoxysilane), 40 parts by weight of tetraglycidyldiaminodiphenylmethane (epoxy equivalent: 116.6 g / eq), and 40 parts by weight of a latent curing agent (epoxy equivalent: 185 g / eq, Novacure HX-3941 manufactured by Asahi Kasei Corporation) Is kneaded in a mortar, and a planetary mixer (MX, manufactured by Sinky Co., Ltd.)
-201) to obtain a uniform adhesive. An adhesive in which the thickener and the conductive particles were uniformly dispersed was obtained.
Also, the inclusion of bubbles in the adhesive was very small. The viscosity was 63 Pa · s (25 ° C., 0.5 rpm, EHD type viscometer).

[0019]

According to the present invention, the filler is uniformly dispersed or kneaded in advance in the liquid component of the adhesive,
Adhesion for circuit connection with minimal change in viscosity by stirring and defoaming with a planetary mixer after mixing the latent curing agent after minimizing the incorporation of bubbles into the connection parts of electronic components, and with excellent connection reliability Agent can be manufactured.

[Brief description of the drawings]

FIG. 1 is a front view showing an operation example in which a filler is uniformly dispersed or kneaded in advance in a liquid component of an adhesive.

FIG. 2 is an explanatory diagram of a rotating unit of the planetary mixer.

FIG. 3 is a sectional view of a rotating unit of the planetary mixer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent closed container 2 Container used for kneading (for example, mortar) 3 Filler 4 Liquid component 5 Balance 6 Worker 7 Glove provided in closed container 1 8 Container containing kneaded material 9 Center of bottom of container 10 Container bottom and One point on the same plane and outside the bottom of the container 11 A rotating body with one point 10 as the central axis outside the bottom of the container 12 Planetary mixer body

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Isao Tsukagoshi 1150 Goshomiya, Oji, Shimodate, Ibaraki Prefecture Inside the Goshonomiya Plant of Hitachi Chemical Co., Ltd. (72) Inventor: Yuko Mochida 48 Wadai, Tsukuba, Ibaraki Prefecture Within Tsukuba Development Laboratory, Hitachi Chemical Co., Ltd.

Claims (6)

[Claims] 1. A method for producing an adhesive for circuit connection, comprising kneading a thickener, a latent curing agent, a liquid epoxy resin, and conductive fine particles as essential components, wherein the thickener is previously dispersed in the liquid component. A method for producing an adhesive for circuit connection, which comprises kneading and previously dispersing and kneading conductive fine particles in a liquid component. 2. A method for producing an adhesive for circuit connection, comprising kneading a thickener, a latent curing agent, a liquid epoxy resin, and conductive fine particles as essential components, wherein the thickener or the conductive fine particles are contained in the liquid component. A method for producing an adhesive for circuit connection, which comprises previously dispersing and kneading the mixture. 3. A method for producing an adhesive for circuit connection, comprising kneading a thickener, a latent curing agent, a liquid epoxy resin, and conductive fine particles as essential components, wherein the thickener and the conductive fine particles are contained in a liquid component. A method for producing an adhesive for circuit connection, which comprises previously dispersing and kneading the mixture. 4. A method for producing an adhesive for circuit connection, comprising kneading a thickener, a latent curing agent, a liquid epoxy resin, and conductive fine particles as essential components, wherein components other than the latent curing agent are previously dispersed and dispersed. A method for producing an adhesive for circuit connection, which comprises kneading. 5. A method for producing an adhesive for circuit connection, comprising kneading a thickener, a latent curing agent, a liquid epoxy resin, and conductive fine particles as essential components, the method comprising adding a thickening agent to the liquid component excluding the latent curing agent. A method for producing an adhesive for circuit connection, comprising dispersing and kneading a viscous agent in advance, and then defoaming the kneaded product and other components including a latent curing agent while mixing and stirring. 6. A method for producing an adhesive for circuit connection, comprising kneading a thickener, a latent curing agent, a liquid epoxy resin, and conductive fine particles as essential components, wherein the adhesive is added to the liquid component excluding the latent curing agent. After previously dispersing and kneading the adhesive, in the step of defoaming while mixing and stirring the other components including the kneaded material and the latent curing agent, the container containing the kneaded material is centered on the center of the bottom surface of the container. Adhesive for circuit connection, obtained by simultaneous demixing and agitation by simultaneous rotation of the rotating motion and the rotating motion that is on the same plane as the bottom of the container and centered on a point outside the bottom of the container. Manufacturing method.