JP3484733B2 - Manufacturing method of circuit board device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a circuit board device. 2. Description of the Related Art Anisotropic conductive elastomer sheets are used to secure electrical connection between circuit elements and circuit boards. In other words, it has conductivity in the thickness direction of the anisotropic conductive elastomer sheet in the pressurized state or in the non-pressurized state, enabling compact connection without using means such as soldering or mechanical fitting. Taking advantage of this feature, an anisotropic conductive elastomer sheet is placed between the circuit element and the circuit board, the positions of the electrodes and conductive parts are aligned, and the circuit element and the circuit board sandwich the anisotropic conductive elastomer sheet. It is used. Further, there can be cited an example in which an anisotropic conductive elastomer sheet is interposed between the liquid crystal display element and the circuit board to secure electrical connection between the circuit board and the liquid crystal display element. As a method for producing an anisotropic conductive elastomer sheet, Japanese Patent Application Laid-Open No. Sho 54-146873 discloses a method in which conductive magnetic particles are dispersed non-uniformly in an elastomer. Japanese Patent Application Laid-Open Publication No. H11-157, discloses a manufacturing method of a type in which conductive magnetic particles are dispersed unevenly in an elastomer and a step is provided between a conductive portion and an insulating portion. However, in recent years, the electrode area, electrode distance, circuit width, and circuit distance of circuit elements and printed circuit boards have become smaller, narrower (finer). Along with this, the conductive portion of the anisotropic conductive elastomer sheet is in the same direction, but there is a problem that it is difficult to align and hold and fix the anisotropic conductive sheet. In order to solve this, a circuit board device in which an anisotropic conductive elastomer sheet and a circuit board are integrated has been proposed in Japanese Patent Application Laid-Open No. Hei 4-151889. SUMMARY OF THE INVENTION Problems to be Solved by the Invention
No. 89, etc., when manufactured by the method disclosed, although the positional relationship between the anisotropic conductive elastomer sheet and the circuit board is accurately maintained, sufficient durability cannot be ensured when repeatedly used. A problem has arisen. [0006] The above problem is caused by the fact that the present invention is arranged in a magnetic field having a uniform magnetic flux density (hereinafter, referred to as a "parallel magnetic field") so that an electrode portion of a circuit board can be provided. The magnetic flux density of the corresponding portion increases, and the magnetic flux density of the portion other than the electrode portion of the circuit board decreases.As a result, the magnetic flux density of the portion corresponding to the electrode portion of the circuit board, Two sets of dies (hereinafter referred to as “die A”, “die B”) whose surfaces processed so as to cause a relative difference with the magnetic flux density of the corresponding portion face each other. ), And using different mold release agents to process the mold A and the mold B, respectively, and to cross-link the portions of the surface of the mold A corresponding to the electrodes of the circuit board to thereby obtain an insulating property. Fluid material and conductive magnetic particles to be elastic polymer material A step of arranging the mixture (hereinafter, referred to as “conductive paste”), a flowable substance (hereinafter, referred to as “elastic polymer substance”) that becomes an insulating elastic polymer substance by crosslinking on the surface of the mold B.
It is called "insulating paste." ) In a layered manner, a step of combining the mold A and the mold B (hereinafter, the mold in this state is referred to as a “prepared mold”), and a parallel magnetic field between magnetic poles in a magnetic field circuit using an electromagnet. A charged metal mold is placed between the magnetic poles of the device capable of generating a magnetic field, and a parallel magnetic field is applied to the charged metal mold before or during cross-linking of the uncrosslinked elastic polymer material in that state. A step of forming an anisotropically conductive elastomer sheet by crosslinking an uncrosslinked elastic polymer material, removing the mold B from the charged mold after crosslinking, and attaching the anisotropically conductive elastomer sheet to the mold A. An insulating elastic polymer material obtained by a method of manufacturing a circuit board device, comprising: a step of obtaining an as-deposited state; and a step of integrating a circuit board and an anisotropic conductive elastomer sheet. inside A plurality of conductive portions conductive particles is formed by densely packed is solved by the anisotropically conductive elastomer sheet are arranged in a state of being insulated by an elastic polymer material insulating from each other. By this method, the disorder of the arrangement of the conductive particles in the conductive part was solved, and the durability at the time of repeated use was improved. [0007] As a method of integration, a mold A and a mold B are combined as a means for integrating the anisotropic conductive elastomer sheet and the circuit board and facilitating the alignment when the circuit board apparatus is formed. After producing an anisotropically conductive elastomer sheet by applying a magnetic field, it is also possible to preferably use alignment with a circuit board in a state where the anisotropically conductive elastomer sheet is adhered to the mold A. An embodiment of the present invention will now be described with reference to FIG.
0 (FIG. 2) will be described with reference to the drawings. FIG. 6 shows the structure of the mold A101 in a sectional direction, and FIG. 3 shows the structure of the mold A101 in a surface direction. The mold A101 is made of a magnetic material on a base 7 which is a magnetic material. A certain magnetic pole 2 is arranged in the same positional relationship as the relative positional relationship between the electrodes 1 of the circuit element 100 shown in FIG. A height difference is provided between the surface of the nonmagnetic layer 3 and the surface of the magnetic pole 2 (hereinafter, this surface is referred to as “the surface of the mold A101”). FIG. 7 shows the structure of the mold B102 in a sectional direction, and FIG. 4 shows the structure of the mold B102 in a surface direction. The mold B102 is a magnetic material on a base 8 which is a magnetic material. A certain magnetic pole 4 is arranged in the same positional relationship as the relative positional relationship between the electrodes 6 of the circuit board 103 shown in FIG. Further, a height difference is provided between the surface of the nonmagnetic layer 5 and the surface of the magnetic pole 4 (hereinafter, this surface is referred to as “the surface of the mold B102”). As a material constituting the base, a commercially available plate-like material may be used as long as it is a material which exhibits ferromagnetism by the action of a magnetic field, does not generate residual magnetism, and has a good cutting workability such as a guide hole processing. Can be used arbitrarily. For example, soft iron, carbon steel, permalloy, ferrite, nickel, nickel alloy, and the like can be cited, and soft iron is particularly preferable in terms of availability. As the material forming the magnetic pole, the same material as the material forming the base can be used. The magnetic pole is formed by a method of cutting the base by machining, electrical discharge machining, or the like, a method of forming plating or the like, or a method of using these in combination. In the case of forming by plating or the like, nickel is preferable from the viewpoint of ease of processing. As the material of the nonmagnetic material, a metal material or an organic material which does not exhibit ferromagnetism under the action of a magnetic field is used.
As the metal material, for example, a material such as copper, brass, or aluminum that can be easily formed by plating, vapor deposition, or the like is used. As the organic material, a general material such as an epoxy resin, an acrylic resin, and a polyimide resin is used. A photo-curable material is preferred from the viewpoint of easy processability. Mold A101, Mold B102 and Circuit Board 1
03, a guide hole 51, a guide hole 52, and a guide hole 5 used for alignment between the mold A101 and the mold B102 and alignment between the mold A101 and the circuit board 103.
3 is open. In each of the guide holes, the surface of the mold A101 and the surface of the mold B102 face each other, and the guide pins are inserted into the guide holes 51 and 52 so that the mold A
When the surface of the mold 101 and the surface of the mold B102 are fixed in a parallel positional relationship, the center line assumes that the relationship between the center of the magnetic pole 2 of the mold A101 and the surface of the nonmagnetic layer 3 is perpendicular. From the center of the magnetic pole 4 of the mold B102 to the non-magnetic layer 5
The center line assumed to be perpendicular to the surface coincides, the surface of the mold A101 faces the surface of the circuit board 103, the guide pins are inserted into the guide holes 51 and 53, and the mold Surface of A101 and circuit board 103
And a center line assumed to be perpendicular to the surface of the non-magnetic layer 3 from the center of the magnetic pole 2 of the mold A101 when the position is fixed to be parallel to the surface of the mold A101. Is opened at a position that satisfies that the center line assumed to be perpendicular to the surface of the circuit board 103 from the center (hereinafter, the satisfied positional relationship is referred to as “correct positional relationship”). .) The diameter of the guide hole is preferably 1.0 mm or more. In this example, a hole diameter of 1.4 mm was used. The diameter of the guide pin is preferably 1.0 mm or more. In this example, a pin diameter of 1.39 mm was used. When the molds A101 and B102 are placed in a parallel magnetic field, the magnetic flux density of the portion corresponding to the electrode portion of the circuit board is increased, and the magnetic flux of the portion other than the electrode portion of the circuit board is increased. As a result, a relative difference is generated between the magnetic flux density of a portion corresponding to the electrode portion of the circuit board and the magnetic flux density of a portion corresponding to a portion other than the electrode portion of the circuit board. This is for moving the conductive magnetic material particles in a small place to a place in which the magnetic flux density is large. First, a mold release agent A is applied to the surface of the mold A101, and dried in an environment of 50 to 150 degrees Celsius. A mold release agent B is applied to the surface of the mold B102, and dried in an environment of 50 to 150 degrees Celsius. There is a difference in the releasability between the release agent A and the release agent B, and the release agent B has a better releasability than the release agent A. As the release agent, those which do not inhibit the crosslinking of the insulating elastic high molecular substance to be crosslinked, the crosslinking temperature from room temperature to 1
Those which are stably present on the mold surface at 50 ° C. for a period of time from 10 minutes to 24 hours are used, and fluorine compounds are used. As the release agent a, a polytetrafluoroethylene-based release agent is used. As the release agent (b), one having a —CF ₃ functional group at the terminal of the compound is used. For example: And so on. Next, a conductive paste 9 is prepared by mixing a flowable substance which becomes an insulating elastic polymer substance by crosslinking and conductive magnetic particles. Air mixed during mixing is removed by putting the mixed conductive paste 9 in a vacuum tank and reducing the pressure in the tank. Examples of the flowable substance used as the conductive paste 9 which becomes an insulating elastic polymer substance by crosslinking include polybutadiene, natural rubber, polyisoprene, styrene-butadiene copolymer rubber, and acrylonitrile-butadiene copolymer. Examples thereof include polymerized rubber, ethylene-propylene copolymer rubber, urethane rubber, polyester rubber, chloroprene rubber, epichlorohydrin rubber, and silicone rubber. In this example, silicone rubber was used. The conductive magnetic particles used in the conductive paste 9 include, for example, particles of a metal such as iron, nickel and cobalt or alloys thereof, or plating of these particles with gold, silver, palladium and rhodium. And non-magnetic metal particles, inorganic particles such as glass beads, or polymer particles plated with a conductive ferromagnetic material such as nickel or cobalt.
Of these, particles of iron, nickel or their alloys are particularly preferable in terms of price, and gold-plated particles can be preferably used in terms of electrical characteristics such as low contact resistance and weather resistance. In this example, nickel particles plated with gold were used. The particle size of the conductive magnetic material used for the conductive haze 9 is preferably 0.01 to 200 μm, and more preferably 1 to 100 μm in consideration of the flexibility of the anisotropic conductive elastomer sheet. is there. In this example, particles having a particle diameter of 28 to 40 μm were used. The mixing ratio of the conductive magnetic particles is from 5 to 50 in volume fraction with respect to the entire mixture of the conductive magnetic particles and the fluid substance which becomes an insulating elastic polymer material by crosslinking. % Is preferred. Particularly, 5 to 15% is preferable. In the present example, it was adjusted to 10%. Next, air mixed with a flowable substance which is used as the insulating paste 10 and becomes an insulating elastic polymer substance by being cross-linked is charged into the vacuum tank by the insulating base 10.
And remove it by depressurizing the tank. Examples of the flowable substance used as the insulating base 10, which becomes an insulating elastic high molecular substance by crosslinking, include polybutadiene, natural rubber, polyisoprene, styrene-butadiene copolymer rubber, acrylonitrile-butadiene. Copolymer rubber, ethylene-propylene copolymer rubber, urethane rubber, polyester rubber, chloroprene rubber, epichlorohydrin rubber, silicone rubber and the like can be mentioned. In this example, silicone rubber was used. Next, the conductive paste is applied to the conductive paste forming area 14 shown in FIG. 8 on the surface of the mold A101 by a printing machine equipped with a metal mask having an opening having the same area and positional relationship as the conductive paste forming area 14. The conductive paste 9 is placed by printing the paste 9. The thickness of the metal mask is 50 to 350 μm
Is preferred. In the present embodiment, the one having a thickness of 150 μm was used. As a printing machine, a screen printing machine was used. Next, an insulating paste is applied to the insulating paste application area 15 shown in FIG. 9 on the surface of the mold B102 by a printing machine equipped with a metal mask having an opening having the same area and positional relationship as the insulating paste application area 15. The conductive paste 10 is placed by printing the paste 10. The thickness of the metal mask is 50 to 350 μm
Is preferred. In the present embodiment, the one having a thickness of 150 μm was used. As a printing machine, a screen printing machine was used. Next, a spacer having a uniform thickness is placed in a mold A10.
1 and a mold B102, and a mold A101.
The surface of the mold A101 and the surface of the mold B102 where the conductive paste 9 is placed in the conductive paste forming basin 14 shown in FIG.
5, the guide pins are inserted into the guide holes 51 and 52 in such a state that the surface of the mold B102 on which the conductive paste 10 is placed is facing each other.
101 and the mold B102 are pressed against the spacer, and the mold A
By ensuring that the surface of the mold 101 and the surface of the mold B102 are parallel to each other, a prepared mold adjusted to the correct positional relationship is obtained. FIG. 10 is a diagram showing a positional relationship when the fitting is performed from the cross-sectional direction of the mold. The thickness of the spacer is preferably between 50 and 5000 μm, particularly preferably between 50 and 350 μm. In the present embodiment, the one having a thickness of 150 μm was used.
Examples of the material of the spacer include copper, brass, aluminum, and stainless steel, which do not exhibit ferromagnetism under the action of a magnetic field. In this example, stainless steel was used. Next, the electromagnet pole 16 (N pole side) and the electromagnet pole 17 (S pole side) in a state where no parallel magnetic field is generated.
Thus, the charged mold is sandwiched (FIG. 11), and a parallel magnetic field is generated between the electromagnet pole 16 and the electromagnet pole 17 in this state, and after applying the magnetic field to the charged mold or while applying the magnetic field, By cross-linking the conductive paste 9 and the insulating paste 10, a conductive part and an insulating part are integrated, that is, an anisotropic conductive elastomer sheet is formed. Next, the charged mold is taken out from between the magnetic poles, and a mold having a moderate rigidity between the mold A101 and the mold B102 and having a thickness smaller (thinner) than the spacer thickness is applied. Since the mold releasability is already different from B102, only the mold B102 can be removed, and as shown in FIG. 12, a state in which the anisotropic conductive elastomer sheet 104 is attached to the mold A101. Can be obtained. In this embodiment, there is moderate rigidity,
For those thinner (thinner) than the spacer thickness, the tip of tweezers was used. In order to obtain a strong adhesive force between the anisotropic conductive elastomer sheet 104 and the circuit board 103, the surface of the circuit board 103 where the electrodes 6 corresponding to the electrodes 1 of the circuit elements 100 (hereinafter, this surface is referred to as The adhesive 13 is applied to the “surface of the circuit board 103” (however, it is preferable that the adhesive 13 is not applied to the surface of the electrode 6 of the circuit board). An adhesive suitable for the insulating elastic high-molecular substance to be used is used. In the case of silicone rubber, a silicone rubber-based adhesive was used. In this embodiment, KE-18
20 (manufactured by Shin-Etsu Chemical Co., Ltd.) was used as an adhesive. Next, a spacer having a uniform thickness is placed in the mold A10.
1 and the circuit board 103, and the mold A10
1 and the surface of the circuit board 103 are opposed to each other, and the guide pins are inserted into the guide holes 51 and 5.
3 and the circuit board 10 from the mold A101 side.
The mold A101 and the spacer are pressed against the circuit board 103, and the surface of the mold A101 and the circuit board 1 are pressed.
03, and the contact between the surface of the conductive portion 11 of the anisotropic conductive elastomer sheet 104 and the surface of the electrode 6 of the circuit board 103 is adjusted to the correct positional relationship. Is cured, and the anisotropic conductive elastomer sheet 104 and the circuit board 103 are integrated. FIG. 13 is a diagram showing the positional relationship when the fitting is performed from the sectional direction of the mold. The thickness of the spacer is preferably between 50 and 5000 μm, particularly preferably between 50 and 350 μm. In the present embodiment, the one having a thickness of 150 μm was used.
In this embodiment, stainless steel was used as the material of the spacer. Also, it is not necessary to use it. Next, the mold A101 which has an appropriate hardness between the mold A101 and the circuit board 103 with the adhesive cured and which is thinner (thinner) than the thickness of the spacer is applied.
Can be easily removed because the mold release processing has already been performed. As shown in FIG. 4, the circuit board device 105 has an anisotropic conductive elastomer sheet 104 adhered to the circuit board 103.
Can be obtained. In this embodiment, the tip of tweezers was used for a material having moderate hardness and thinner (thinner) than the spacer thickness. In this way, the anisotropic conductive elastomer sheet and the circuit board are integrated, and the conductive particles in the conductive portion of the anisotropic conductive elastomer sheet are regularly arranged.
An insulating portion free of conductive particles is obtained. Hereinafter, specific examples and comparative examples will be described. Example 1 A QFP pattern schematically shown in FIG.
A circuit board device in which an anisotropic conductive elastomer sheet is integrated on a circuit board made of glass epoxy resin having a thickness of t = 2.5 mm and a seed electrode width of 0.1 in which 200 lead electrodes are arranged at 5 mm. To manufacture. The anisotropic conductive elastomer sheet has a conductive part width of 0.1 in the QFP pattern.
mm, projection height of conductive part 0.05 mm, thickness of insulating part 0.15
mm. 3 and 7, the arrangement of the magnetic poles of the mold and the spacer thickness are set. Room temperature-curable silicone rubber was used as the insulating polymer elastic material, and conductive magnetic particles of nickel having an average particle size of 28 to 40 μm were mixed at a ratio of 10% by volume, and used as a conductive paste. It was applied by screen printing on the mold (A) that had been treated with the mold agent. Silicone rubber was applied by screen printing on the release agent-treated (B). This is combined with a mold with a guide pin, and 500
Crosslinking was performed at 60 ° C. for 3 hours under a parallel magnetic field of 0 Gauss to produce an anisotropic conductive elastomer sheet. With the mold removed, the anisotropic conductive elastomer sheet is adhered to the mold (A), and the silicone-based adhesive KE-1820 is adhered to a blade-coated circuit board, and is pressed at 150 ° C. for 2 hours in a press machine. And cured to produce a circuit board device. COMPARATIVE EXAMPLE 1 A circuit board device was prepared in the same manufacturing process as in Example 8 in Japanese Patent Application Laid-Open No. 2-273448, using the conductive paste of Example 1 and the insulating polymer elastic material. Test Example With respect to each circuit board device manufactured as described above, the resistance value of the lead electrode in the electrical connection was measured.
The resistance value was measured in a state where a pressing force of 20% compression was applied in the thickness direction of the conductive portion of the anisotropic conductive elastomer sheet. Table 1 shows the average value of the resistance value after the first compression and the average value of the resistance value after 100,000 times compression. [Table 1] According to the method of the present invention, it is possible to obtain a circuit board device having good durability in which the anisotropic conductive elastomer sheet and the circuit board are integrated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a circuit board device. FIG. 2 is a diagram of an electrode arrangement of a circuit element as viewed from an electrode side. FIG. 3 is a diagram illustrating a magnetic pole arrangement of a mold A viewed from a magnetic pole side. FIG. 4 is a diagram showing a magnetic pole arrangement of a mold B viewed from a magnetic pole side. 5 is a diagram of an electrode arrangement of a circuit board using a circuit board device corresponding to the circuit element of FIG. 2 as viewed from the electrode side. FIG. 6 is a cross-sectional structure of a mold A. FIG. 7 is a sectional structure of a mold B; FIG. 8 is a diagram illustrating a formation region of a conductive paste. FIG. 9 is a diagram showing a region where an insulating paste is formed. FIG. 10 is a diagram showing a positional relationship when a mold A and a mold B are fitted together as viewed from a cross-sectional direction. FIG. 11 is an explanatory view schematically showing an apparatus used for manufacturing. FIG. 12 is an explanatory cross-sectional view illustrating an example of manufacturing a circuit board device. FIG. 13 is an explanatory sectional view illustrating a production example of the circuit board device. FIG. 14 is an explanatory cross-sectional view illustrating an example of manufacturing a circuit board device. [Description of Signs] 1 Electrode 2 Magnetic pole 3 Non-magnetic layer 4 Magnetic pole 5 Non-magnetic layer 6 Electrode 7 Base 8 Base 9 Conductive paste 10 Insulating paste 11 Conductive section 12 Insulating section 13 Adhesive layer 14 Conductive paste forming area 15 Insulation paste application area 16 Electromagnetic pole (N pole) 17 Electromagnetic pole (S pole) 50 Guide hole 51 Guide hole 52 Guide hole 53 Guide hole 100 Circuit element 101 Mold A 102 Mold B 103 Circuit board 104 Anisotropic conductivity Elastomer sheet 105 Circuit board device

Continuation of the front page (56) References JP-A-4-151889 (JP, A) JP-A-54-146873 (JP, A) JP-A-53-147772 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) H01B 13/00 501 H01B 5/16 H05K 1/11 H05K 3/32

Claims (1)

(57) [Claim 1] A circuit board comprising: a circuit board; and an anisotropically conductive elastomer sheet integrally formed on a surface of the circuit board. A plurality of conductive portions in which conductive particles are densely filled in an insulating elastic polymer material are arranged in a state in which they are insulated from each other by an insulating elastic polymer material. A method for manufacturing a circuit board device disposed on an electrode of a substrate, wherein the magnetic flux density is placed in a uniform magnetic field,
The magnetic flux density of the portion corresponding to the electrode portion of the circuit board is increased, and the magnetic flux density of the portion other than the electrode portion of the circuit board is reduced. As a result, the magnetic flux density of the portion corresponding to the electrode portion of the circuit board and the circuit Different mold release agents are used by using a pair of molds in which the surfaces processed so as to cause a relative difference between the magnetic flux densities of portions corresponding to portions other than the electrode portion of the substrate face each other. A step of processing the mold by using a fluid material that becomes an insulating elastic polymer material by being cross-linked to a portion of one surface of the mold that corresponds to an electrode of a circuit board; A step of disposing a mixture of magnetic particles, a step of disposing a flowable substance that becomes an insulating elastic polymer material by crosslinking on the other surface of the mold, and a step of disposing the mold; The process of combining magnetic fields with an electromagnet Between the magnetic poles of the apparatus capable of generating a parallel magnetic field between the magnetic poles in, place the charged already mold,
In this state, before or while cross-linking the uncrosslinked elastic polymer material, a parallel magnetic field is applied to the charged mold to crosslink the uncrosslinked elastic polymer material to form an anisotropic conductive elastomer sheet. Removing the mold B from the charged mold after cross-linking, and obtaining a state in which the anisotropic conductive elastomer sheet remains attached to the mold A, and removing the circuit board and the anisotropic conductive elastomer sheet. A method of manufacturing a circuit board device, comprising: