JPH05183261A - Manufacture of conductor circuit board - Google Patents

Abstract

PURPOSE:To obtain a manufacturing method of a conductor circuit board wherein chip parts are mounted on a circuit board without soldering, by using general adhesive agent such as an aerobic adhesive agent having instantaneous adhering properties and hot-melt resin pressure sensitive adhesive agent. CONSTITUTION:Ink which contains adhesive resin, catalytic colloidal metal powder, spherical conductive pigment, and conductive whisker is screen-printed on a circuit board and cured. The screen-printed part is subjected to electroless plating, and a porous conductor circuit board having uneveness is constituted, on which chip parts are mounted by using adhesive agent. Thereby a conductor circuit board can be obtained. Ink which contains adhesive resin, catalytic coloidal metal powder, and conductive whisker is screen-printed on the circuit board and cured. The screen-printed part is subjected to electroless plating by using electroless plating bath, and chip parts are mounted thereon by using an adhesive agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a conductor circuit board. More specifically, the present invention relates to a method for manufacturing a conductor circuit board in which a chip component is mounted on the circuit board with a general adhesive without soldering.

[0002]

2. Description of the Related Art Conventionally, soldering has been generally used to mount chip components such as Ic, resistors and capacitors on a circuit board. However, various circuit boards have been developed with the recent advances in precision and sophistication of electronic parts,
Among them are boards without solder, fine boards that short-circuit between conductor circuits with solder, boards that cannot withstand soldering temperature, etc.Therefore, a new chip component mounting method that replaces soldering is desired. ..

As an alternative to soldering, for example,
A method of mounting a chip component on a circuit board using an anisotropic conductive adhesive is known. According to this method, a conductor circuit board that can be practically used is manufactured, but there is a problem that the defective product rate is high. Moreover, the anisotropic conductive adhesive is very difficult to manufacture, the cost is extremely high, and various restrictions are involved in mounting the chip parts using the adhesive, which makes it difficult to apply it to mass production.

When components are mounted with a general adhesive such as a hot melt resin pressure sensitive adhesive, the resulting circuit exhibits almost no conductivity and is difficult to put into practical use.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to use a general adhesive such as an anaerobic adhesive or a hot melt resin pressure-sensitive adhesive having an instant adhesive performance without depending on soldering, and a circuit board. Another object of the present invention is to provide a method of manufacturing a conductor circuit board on which a chip component is mounted.

Another object of the present invention is to provide a method for producing a conductor circuit board which exhibits high conductivity and excellent electrical performance, has a strain absorption performance capable of withstanding severe operating conditions, and has a very low defective product rate. To do.

[0007]

According to the present invention, an ink containing an adhesive resin, a catalytic colloidal metal powder, a spherical conductive pigment and a conductive whisker is screen-printed and cured on a circuit board, and the screen-printed portion is then cured. Apply electroless plating,
A method of manufacturing a conductor circuit board, characterized in that a chip component is mounted thereon by using an adhesive (hereinafter referred to as a first invention), and an adhesive resin, a catalytic colloidal metal powder and a conductive whisker on a circuit board. The ink containing is cured by screen printing, and the screen-printed portion is subjected to electroless plating using an electroless plating bath containing a spherical conductive pigment, and a chip component is mounted thereon using an adhesive. The present invention relates to a characteristic method for producing a conductor circuit board (hereinafter referred to as a second invention).

The first invention will be described below.

According to the first invention, first, a catalytic ink is screen-printed on a circuit board to form a catalytic film,
An electroless copper base treatment is performed to form a silver plating coating layer.

The circuit board is not particularly limited, and any conventional one can be used, and the material and shape can be appropriately selected from a wide range according to the application and purpose.

The ink contains an adhesive resin, a catalytic colloidal metal powder, a spherical conductive pigment and a conductive whisker.
As the adhesive resin, known ones can be used, such as a substrate material or a flexible circuit board, an elastomer circuit board,
Polyester, urethane, acrylic, epoxy, phenol, silicone resin, fluorine resin, silicone rubber, fluorine rubber, NBR, butadiene according to the intended use such as multilayer circuit board, shaping circuit board, power circuit board, high frequency circuit board, etc. Examples thereof include rubber, and among them, urethane resin and fluorine resin are preferable. Examples of commercially available products include SB104 [polyurethane resin, manufactured by Nippon Polyurethane Industry Co., Ltd.] / C2507 [block isocyanate,
Made by Nippon Polyurethane Co., Ltd., Cefural Coat A201
TB [Fluorocarbon resin, Central Glass Co., Ltd.] / C25
07 etc. can be mentioned. Resin SB104 / C2
507 and A201TB / C2507 are usually dissolved in an organic solvent (for example, γ-butyrolactone, carbitol acetate, methyl ethyl ketone, etc. or a mixture thereof), and SB104 / C2507 has a resin solid content of about 25 to 30%, and Cefraralcoat A201TB / C2507. At 35 to 45
% Is suitable for use. Two or more kinds of resins may be mixed and used.

The catalytic colloidal metal powder is a colloidal metal powder having a metallic catalytic property. By mixing the colloidal metal powder, a plating film can be formed on the resin film. As the colloidal metal powder, known ones can be used, but Cu, Ni, Co, Fe, M having catalytic ability is taken into consideration in consideration of economical efficiency.
Colloidal powders such as n are preferred. The particle size of the catalytic colloidal metal powder is not particularly limited, but is usually 0.3 μm or less in particle size, and is used as small as possible by being dispersed in primary particles. Examples of commercially available products include MDPO30 [colloidal Cu,
Sumitomo Metal Mining Co., Ltd.], SNP110 [Colloid N
i, manufactured by Sumitomo Metal Mining Co., Ltd.] and the like. The compounding amount of the catalytic colloidal metal powder is not particularly limited, but is usually about 40 to 80% (% by weight, the same applies below) of the total amount of the ink, preferably about 45 to 70%.

By blending the spherical conductive pigment, unevenness is formed on the surface of the resin film and further on the surface of the metal plating, and a conduction path in the thickness direction is formed. That is, when the component is mounted with the adhesive, the concave portion of the adhesive portion, which is included in the irregularities on the surface of the circuit board, has a reinforcing property, and the convex portion has a function of having a conductive path. Therefore, it is preferable that the spherical conductive pigment has a required characteristic that the particle diameter is as uniform as possible and that it is porous. Also, the particle diameter of the spherical conductive pigment is preferably larger than the set resin film thickness. Specific examples of the spherical conductive pigment include carbon beads, Ni, Cu, and alloy powders thereof. Examples of commercially available products include carbon beads MC10
20 (manufactured by Nippon Carbon Co., Ltd.) and the like. The compounding amount of the spherical conductive pigment is not particularly limited, but is usually about 1 to 30%, preferably about 2 to 12% of the total amount of the ink.

By blending the conductive whiskers, the adhesion between the circuit board and the resin film is further enhanced. Specific examples of the conductive whiskers include, for example, graphite whiskers, carbon-coated potassium titanate whiskers, copper-coated potassium titanate whiskers, nickel-coated potassium titanate whiskers, and the like, among which an aspect ratio of 10 or more. Is preferred. Examples of commercially available products include Graphite Whiskers [Asahi Kasei Corp.
Manufactured by Otsuka Chemical Co., Ltd., and the like. The compounding amount of the conductive whiskers is not particularly limited,
Usually, it is about 3 to 30%, preferably about 5 to 20% of the total amount of ink.

Further, the above ink may contain porous beads. By blending the porous beads, it is possible to improve the adhesiveness due to the anchor effect on the binding resin, and improve the plating property due to the homogeneous supporting force of the catalyst. Examples of the porous beads include porous carbon beads, porous plastic beads, porous ceramic beads, and the like. Examples of commercially available products include carbon beads [manufactured by Nippon Carbon Co., Ltd.], plastic beads DP5
[Kanebo Co., Ltd.] and ceramic beads [Fuji Devison Chemical Co., Ltd.]. The compounding amount of porous beads is not particularly limited, but usually 10% of the total amount of ink is used.
% Or less, preferably 8% or less.

An ink is obtained by mixing the above-mentioned components by a conventional method. For example, it may be mixed by using a three-roll, ultrasonic homogenizer, or the like.

After screen printing on a circuit board using this ink, the printed layer is cured. Screen printing is possible with a screen of # 350 to # 200 with a total thickness of 70 to 120 μm and a pitch of up to 300 μm. The printing amount of the ink is not particularly limited, but the printing is usually performed so that the film thickness of the resin film after curing and drying is usually about 12 to 30 μm, preferably about 15 to 25 μm. The curing conditions are not particularly limited,
Usually, the temperature may be about room temperature to 180 ° C. and the time may be about 0.5 to 2 hours. In this way, the sheet resistance (R ₀ ) of 0.01
Conductor circuits of Ω / □ or less are formed.

Next, electroless plating is performed using an electroless plating bath containing a chelating agent to form a plating layer on the conductor portion (resin film) of the circuit board. If the conductor circuit has an area resistance of 0.01 Ω / □ or less, electroless plating is sufficient.

As the electroless plating bath, any of those commonly used in this field can be used, and among them, the Cu plating bath which can obtain a low resistance plating film is preferable. Specifically, for example, Cell Rex [manufactured by EEJA], Mighty CH [manufactured by Yamato Special Co., Ltd.], MK450 [manufactured by Muromachi Chemical Co., Ltd.], Enplate Cu701 [manufactured by Japan Metal Finishing Company] , Shipley Kimerposit 328L [made by Shipley Far East], CU
ST201 (manufactured by Hitachi Chemical Co., Ltd.) or the like can be used. As the Cu chelating agent added to this electroless plating bath, known ones can be used, and among them, a quadrol bath, an EDTA bath and the like are preferable. Conditions for electroless plating may be the same as usual, for example, 15 at a temperature of 40 to 60 ° C.
It should be about 30 minutes. Thereby, the thickness is 1-3 μm
A plating layer is formed to some extent, and the sheet resistance is 0.01 to 0.006Ω /
□ is obtained.

A chip component is mounted on a predetermined portion of the plating layer thus formed using an adhesive. Known adhesives can be used, for example, anaerobic adhesives such as anaerobic UV common acrylate adhesives, hot-melt resin pressure-sensitive adhesives, etc., and anisotropic conductive adhesives can also be used. .. Commercially available adhesives that can be preferably used in the present invention include, for example, Arontite BU series (manufactured by Toagosei Kagaku Co., Ltd.), HARDLOC TM3.
01 [manufactured by Denka], Diabond SG-11 [manufactured by Nogawa Chemical Co., Ltd.], Y-800 [Cemedine Co., Ltd.]
], Chip Bonder 3601 [Nippon Loctite Co., Ltd.]
And so on. Incidentally, in order to join the bare chips by face-down, an adhesive in which the ionic substance is controlled to 4 ppm or less is preferable.

In the present invention, as shown in the second invention, the conductor portion is screen-printed on the substrate without adding the spherical conductive pigment to the ink, and then the electroless plating bath containing the spherical conductive pigment is used. Electroless plating may be performed to mount a chip component to form a conductor circuit. Others are the same as those of the first invention except that the spherical conductive pigment is used in the subsequent step.

[0022]

EXAMPLES The present invention will be further clarified by the following examples.

Example 1 Using a varnish having a resin solid content of 35% [solvent: γ-butyrolactone / carbitol acetate (1: 1)], the compositions A, B and C shown in Table 1 were prepared and rolled with a three-roll mill. The ink was prepared by mixing.

Using this ink, a zigzag pattern with a thickness of # 200 and a total thickness of 100 μm, n = 1000, is formed with a thickness of 14
A 4 μm polyester film (trade name: Lumirror, manufactured by Toray Industries, Inc.) was printed on a substrate and cured and dried at 150 ° C. for 2 hours to form a resin film (conductor portion). Resin film thickness is 22μ
It was m. Next, Cu electroless plating bath [CUST20
1 manufactured by Hitachi Chemical Co., Ltd.], and Cu electroless plating was performed at 60 ° C. for 15 minutes. The resistance values are different for each composition of A, B and C, and are shown in Table 2. From the table, the surface unevenness effect and the occlusion effect were sufficiently obtained.

To this, a chip resistance of 10Ω from Kamaya Denki was joined with an adhesive [Rocktite Chip Bonder 3601, manufactured by Nippon Roctite Co., Ltd.]. Table 2 shows the junction resistance including the chip resistance of 10Ω.

[0026]

[Table 1]

[0027]

[Table 2]

Example 2 An ink having the composition shown in Table 3 was used and electroless plating was performed in the same manner as in Example 1. The resistance values of D, E and F are shown in Table 4 and compared with Example 1. It can be seen that it forms a porous film.

[0029]

[Table 3]

[0030]

[Table 4]

Example 3 Using the ink having the composition shown in Table 5, screen printing, dry curing and Cu electroless plating were performed on a PET circuit board in the same manner as in Example 1 and immediately after washing with water, an Au plating bath [M-
Au-1, manufactured by Nihon Mining Co., Ltd.] at a temperature of 70 ° C.
Au plating was carried out for 5 minutes to obtain an Au-Cu / PET circuit board.

The Au-Cu / PET circuit board and the ITO / glass transparent conductive circuit board are sealed with a sealing machine [Morfit HM.
2150, manufactured by Daiso Co., Ltd., and heated and pressed at a pressure of 39 kg / cm ² and a temperature of 150 ° C. for 10 seconds to bond.

The resistance value and the seal resistance value of the plated film of the obtained joined body were measured. The data obtained here is an average value of n = 20 measurements. The results are shown in Table 6. It is understood that in this type of bonding, anisotropic conductive bonding can be performed with a general hot melt agent or an adhesive agent of an elastomer.

[0034]

[Table 5]

[0035]

[Table 6]

[0036]

Since the conductor circuit obtained by the method of the present invention has the uneven surface and the wiring electrode portion which is porous, the electrode portion conduction path of the component mounted through the adhesive layer can be obtained. ..

Since parts can be mounted bare, a thin type,
Compact and high-density mounting is possible. The conductor circuit board of the present invention can be mounted on components with a general adhesive, and the material and shape of the circuit board can be selected from a wide range.

Claims (2)

[Claims] 1. An ink containing an adhesive resin, a catalytic colloidal metal powder, a spherical conductive pigment and a conductive whisker is screen-printed and cured on a circuit board, and the screen-printed portion is subjected to electroless plating. A method for manufacturing a conductor circuit board, characterized in that a chip component is mounted on the substrate using an adhesive. 2. An ink containing an adhesive resin, a catalytic colloidal metal powder and a conductive whisker is screen-printed and cured on a circuit board, and an electroless plating bath is applied to the screen-printed portion by using an electroless plating bath. A method of manufacturing a conductor circuit board, which comprises applying a chip component thereto by using an adhesive.