JP2810554B2 - Circuit board manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a circuit board, and more particularly to a method of manufacturing a circuit board used for an optical device such as a camera, a home appliance, a computer, a word processor or a measuring device.

[0002]

2. Description of the Related Art Conventionally, a general method of manufacturing a circuit board is to form a circuit pattern of a copper foil on an insulating substrate by photolithography or screen printing using a conductive paste, and then apply a solder resist or the like. In this method, an insulating layer is provided by coating the surface of a circuit, and then a conductive paste is applied to the surface of the insulating layer to form a shield layer.

As a method of shielding electromagnetic waves, there is a method of shielding a circuit board by surrounding it with a sheet metal, in addition to the method of providing the above-mentioned shield layer. The insulating layer on the circuit pattern is also provided by laminating a dry film.

[0004]

However, according to the conventional method of manufacturing a circuit board, since the thickness of the insulating layer is reduced at the corners of the copper wires constituting the circuit, the insulating layer is easily damaged at this portion. . Further, in the conventional method of manufacturing a circuit board, air bubbles and the like are mixed between copper wires, which easily causes insulation breakdown or insulation failure, which has been a serious problem. Further, the conventional circuit board manufacturing method has a problem in terms of cost because the process is complicated and the manufacturing time is long.

Further, the conventional method of shielding a circuit board by surrounding it with a sheet metal requires a large space for installing the sheet metal and is not suitable for miniaturization of a product.

The present invention has been made in order to improve such disadvantages of the prior art, and has a uniform insulating layer and shield layer on a circuit pattern, no insulation failure, and an electromagnetic wave shielding effect. It is an object to provide a high circuit board and a method for manufacturing the same.

[0007]

According to the present invention, there is provided a method of manufacturing a circuit board, comprising: a first step of forming a circuit pattern composed of conductive wires on the board; and a second step of coating the circuit pattern with a first insulating film. And a third step of coating the first insulating film with a conductive film. At least in the third step, the substrate is immersed in an electrodeposition paint to make the conductive wire an electrode. It is characterized by using an electrodeposition coating method.

[0008]

[0009] The circuit board of the present invention can be used for optical devices such as cameras, home appliances, word processors, computers,
Alternatively, it is used for all electric products such as measuring instruments. As shown in FIG. 1, a circuit board according to the present invention has a first insulating film 4 covering the periphery of a conductive wire 2 formed on an insulating substrate 1, and a conductive film surrounding the first insulating film 4. 3 is to coat. The conductive film 3 is a shield layer that shields electromagnetic waves. A circuit pattern is formed on the insulating substrate 1 by the conductor 2. The conductor 2 is preferably formed of copper. The periphery of the conductive film 3 is further covered with an insulating film 5 as necessary. The insulating film 5 is for preventing the circuit board of the present invention from contacting other components and short-circuiting when the circuit board of the present invention is installed on an electric appliance.

In the circuit board of the present invention, at least the film 3 among the films 3, 4, and 5 is formed by an electrodeposition coating method. The film formed by the electrodeposition coating method is finally cured by irradiating heat or light.

In the electrodeposition coating method, a pair of electrodes are arranged in a solution in which a substance to be a film is dissolved (hereinafter referred to as an electrodeposition coating), and a direct current voltage is applied thereto, whereby the above substances are attached to the electrodes. Things. Therefore, in the present invention, the conductive wire 2 formed on the substrate serves as one electrode. As the other electrode, for example, a stainless plate may be used.

[0012] Electrodeposition coating methods have been conventionally proposed. For example, Japanese Patent Application Laid-Open No. 55-11175 proposes a method of applying an electrodeposition coating twice.
The present applicant has also proposed in JP-A-2-6564 an electrodeposition paint containing a ceramic powder and a fluorine resin powder.

The insulating substrate 1 has a generally known structure.
For example, an insulating substrate such as a polycarbonate resin, a polyetherimide resin, a glass fiber-filled ABS resin, and a glass epoxy resin can be used.

The circuit pattern of the conductor 2 can be formed by a generally known photolithography technique.
That is, for example, a copper foil is laminated on the insulating substrate 1,
Further, after applying a resist on the copper foil, a circuit pattern can be formed by exposure using a mask having a desired pattern, followed by development and etching.

An insulating film 4 is formed around the conductor 2 by an electrodeposition coating method using an electrodepositable resin.

Various resins have been studied for the electrodeposition coating method. In order for the resin to be able to be electrodeposited, it must be charged when it is used as an electrodeposition paint. When a DC voltage is applied, the charged resin is drawn to the anode or the cathode and deposits on the electrode to form a film. As the resin used in the present invention, for example, resins conventionally used in the electrodeposition coating method such as acryl / melamine type, acrylic type, epoxy type, urethane type and alkyd type can be used.

The resin used in the present invention may be an anionic resin or a cationic resin, but practically a water-soluble resin having a carboxyl group or a water-dispersible resin is preferred. The resin prepolymer having a carboxyl group is dissolved or dispersed in water by being neutralized by ammonia or an organic amine.

The resin concentration in the electrodeposition paint is preferably in the range of 5 to 20% by weight, more preferably 7 to 15% by weight.

The electrodeposition paint used in the present invention is preferably one in which a desired resin is dissolved or dispersed in water. However, the electrodeposition paint may further contain an alcohol-based or glycol ether-based organic solvent. I don't care. A few percent content of organic solvent is sufficient.

The insulating film 4 may contain ceramic powder. When the insulating film 4 contains ceramic powder, it can be sufficiently cured at a low temperature, for example, about 90 to 100 ° C. when the insulating film 4 is cured by applying heat. As a result, a circuit board free from thermal deformation can be obtained.

When an electrodeposition film is formed using an electrodeposition coating material containing ceramic powder, it is not clear why the thermosetting is performed at a low temperature, but the surface of the ceramic powder is immediately oxidized. Unlike metal particles, it is considered that the powder surface is maintained in a stable state while being activated to some extent, so that the powder surface becomes a cross-linking point at the time of curing to accelerate the curing of the electrodeposited film.

Examples of the ceramic powder contained in the insulating film 4 include aluminum oxide, titanium nitride, manganese nitride, tungsten nitride, tungsten carbide,
Lanthanum nitride, aluminum silicate, molybdenum disulfide,
Examples include titanium oxide, graphite, and silicate compounds.

If the particle size of the ceramic powder is too large, the insulating film 4 is excessively hardened and becomes brittle. On the other hand, if the particle size is too small, a sufficient effect cannot be obtained. Therefore, the average particle diameter of the ceramic powder is 0.1 to 5 μm, particularly 0.5 μm.
２2 μm is preferred.

The amount of the ceramic powder contained in the electrodeposition coating material used for forming the insulating film 4 is such that the coating film 4 has good physical properties, such as good adhesion, and can be sufficiently cured even at a low temperature. For this reason, 0.5 to 30 parts by weight, especially 2 to 30 parts by weight of the ceramic powder is added to 100 parts by weight of the electrodepositable resin.
It is preferable to disperse 25 parts by weight. The amount of eutectoid of the ceramic powder in the insulating film 4 is 10 to 30 wt%, especially 1 to 30 wt%.
5-25 wt% is preferable.

When electrodeposition coating is performed using an electrodeposition coating material containing powder, the powder is deposited in the formed film because resin molecules are adsorbed around the powder particles in the electrodeposition coating material. Have been
This is probably because the powder moves in the electrode direction as the resin molecules are attracted to the electrode.

After the formation of the insulating film 4, a conductive film 3 serving as a shield layer is formed around the insulating film 4. The conductive film 3 is formed by performing electrodeposition coating using an electrodeposition paint containing a conductive powder. As the conductive powder contained in the electrodeposition paint,
A ceramic powder whose surface is metal-plated (hereinafter, metallized ceramic powder) or a natural mica powder whose surface is metal-plated (hereinafter, metallized natural mica powder) is preferable. Metallized ceramic powder or metallized natural mica powder
Either one of them may be contained in the electrodeposition paint, or both may be mixed and contained. When the metallized ceramic powder or the metallized natural mica is contained in the electrodeposition paint, when the heat treatment is performed after the completion of the electrodeposition to cure the electrodeposited film, the heating temperature is usually set to 130 to
It is preferable that 180 ° C. can be completely cured at a low temperature of 90 ° C. to 100 ° C.

As the metallized ceramic powder and the metallized natural mica powder used in the present invention, for example, Cu, N
Those plated with i, Ag, Au, Sn or the like are used. For plating on the surface of these powders, Cu, Ag and Ni can be suitably used from the viewpoint of shielding properties and cost. Electroless plating is suitable as a plating method for the powder surface. The plating thickness on the powder surface is 0.05
When the thickness is from 3 to 3 μm, particularly from 0.15 to 2 μm, excellent shielding properties and good physical properties of the coating film at the time of low-temperature curing can be obtained. When the plating is formed thicker than 3 μm, the surface characteristics are similar to those of the metal particles, and the surface is extremely active. Therefore, the plating is oxidized in the air and the curing of the electrodeposited film at a low temperature tends to be insufficient.

In the formation of Ni plating on a powder, an aqueous suspension of the powder is prepared as disclosed in, for example, Japanese Patent Application Laid-Open No. 61-26979. To the surface of the powder by adding an electroless nickel plating aging solution, to obtain a low phosphorus content, e.g.
% Or less, the conductivity is improved, and an electrodeposition film having almost the same shielding properties as the Cu plating powder can be formed.

As the ceramic powder used for the conductive powder, the same ceramic powder as that contained in the insulating film 4 can be used. Examples of natural mica include phlogovite mica, sericite mica, and muscobite mica.

The average particle size of the metallized ceramic powder or metallized natural mica is 0.1 to 5 μm, preferably 0.1 to 5 μm.
The range of 5 to 2 μm is desirable, and if it is less than 0.1 μm, the secondary aggregating action is large, and if it exceeds 5 μm, it is not preferable because of sedimentation or cosmetic problems.

As the conductive powder, in addition to metallized ceramic powder and metallized natural mica, resin powder (hereinafter, metallized resin powder) whose surface is plated with metal or metal powder can also be used.

As the resin powder used for the metallized resin powder, for example, fluorine resin, polyethylene resin, acrylic resin, polystyrene resin, nylon and the like can be used. As the metal plating applied to the surface of the resin powder, the same metal plating as in the case of the metallized ceramic powder can be used. The average particle size of the metallized resin powder is the same as that of the metallized ceramic powder.

As the metal powder, for example, Au, Pd, A
g, Ni, Cu, Sn, Co, Mn, Fe, Te and the like powder. The average particle diameter of the metal powder is 0.01
-5 μm, preferably 0.05-4 μm, and more preferably 0.0
A range of 5 to 0.1 μm is desirable. If it is less than 0.01 μm, a secondary agglomeration action occurs, and if it exceeds 5 μm, the powder sediments in the electrodeposition paint, which is not preferable. The metal powder is preferably manufactured using, for example, a thermal plasma evaporation method.

In the present invention, the particle size of the conductive powder is as follows:
It is a value measured using a centrifugal sedimentation type particle size distribution analyzer.
What was actually used as this measuring instrument is SACP-3 (manufactured by Shimadzu Corporation).

The content of the conductive powder in the electrodeposition paint is as follows:
0.2 to 30 parts by weight, preferably 10 to 20 parts by weight, and more preferably 7 to 15 parts by weight with respect to 100 parts by weight of the electrodepositable resin.

The conductive powder in the conductive film 3 can be identified by an X-ray microanalyzer, and the amount of eutectoid of the conductive powder can be measured by analyzing by thermogravimetric analysis. The amount of eutectoid of the conductive powder in the coating film 3 is 5 to 50.
wt%, especially 10 to 40 wt%, furthermore 15 to 35 wt%
% Is preferred.

As the conductive powder contained in the conductive film 3, only one of metalized ceramic powder, metalized natural mica powder, metalized resin powder and metal powder may be used. Two or more kinds such as metalized ceramic powder and metal powder may be mixed and used. Preferably, one or two kinds of conductive powder selected from metallized ceramic powder and metallized natural mica powder, and one or two kinds of conductive powder selected from metallized resin powder and metal powder It is good to mix and use. This is because the metal powder and / or the metallized resin powder fill the voids of the metallized ceramic powder and / or the metallized natural mica powder in the conductive film 3 and the contact area between the powders increases. Therefore, the shielding property is further improved, and the conductive film 3 can be cured at a low temperature by the action of the metallized ceramic powder and / or the metallized natural mica powder. In this case, the mixing ratio of the conductive powder is such that the metallized resin powder and the metal powder are mixed with 100 parts by weight of one or two types of conductive powder selected from metallized ceramic powder and metallized natural mica powder. It is preferable that one or two kinds of conductive powders selected from the body be 20 to 300 parts by weight.

By forming the conductive film 3 by the electrodeposition coating method, the conductive powder is deposited in the conductive film 3 at a high density, and exhibits an excellent shielding function even in the case of a thin film.

After the formation of the conductive film 3, an insulating film 5 is further formed around the conductive film 3 if necessary. The insulating film 5 is the insulating film 4
Using the same material as described in the above, the insulating film 4
It may be formed in the same manner as described above. Therefore, the insulating film 5 may or may not contain ceramic powder. The ceramic powder may be contained in both the insulating layer 4 and the insulating layer 5, or may be contained in only one of them. Also, neither the insulating layer 4 nor the insulating layer 5 may contain ceramic powder.

After the insulating film 4, the conductive film 3 and the insulating film 5, if necessary, are formed around the conductor 2, the insulating films 4, 5 and the conductive film 3 are formed by heat, light or both heat and light. To cure. The energy for curing the resin may be heat or light, but heat is preferred because it can be applied uniformly and easily. The temperature for curing the film and the heating time are preferably from 90 to 100 ° C. and from 20 to 180 minutes. Further, the insulating film or the conductive film can be cured with energy other than heat and light.

The thickness of the insulating film 4 is 5 to 30 μm, and
２５25 μm is preferred.

The thickness of the conductive film 3 is 7 to 40 μm,
0-25 μm is preferred.

The thickness of the insulating film 5 provided as required is 10 to
It is preferably 30 μm, more preferably 10 to 25 μm.

When the insulating films 4, 5 and the conductive film 3 are formed by an electrodeposition coating method, they are immersed in an electrodeposition coating material together with the other electrode using a conductive wire on the substrate as an electrode. The temperature of the electrodeposition paint is preferably 20 to 25 ° C., and the concentration of the water-concentrated ion is preferably pH 8 to 9. Further, the applied voltage is preferably a DC voltage of 50～170V, current density 0.5~3A / dm ^2, treatment time is preferably 1 to 5 minutes. The type of resin used for the insulating films 4 and 5 and the conductive film 3 may be changed for each film.

[0045]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 Using a glass epoxy resin substrate having a thickness of 0.6 mm laminated with a 18 μm copper foil, a negative resist (OMR-83, manufactured by Tokyo Ohka Co., viscosity 450c)
p) was applied by spinner to form a photosensitive material layer having a thickness of 5 μm. Subsequently, exposure and development were performed using each pattern mask having a line width of 0.5 to 50 mm and a space of 1 to 20 mm. Next, using a copper etchant (Alpha-in, manufactured by Uemura Kogyo Co., Ltd.), etching was performed by a spray method to form a copper pattern circuit.

Thereafter, using an electrodeposition paint obtained by diluting an acrylic / melamine resin (trade name: Hanibright CL-1; manufactured by Honey Kasei Co., Ltd.) to a concentration of 15 wt% using demineralized water,
Under a condition of pH 8.5 and a bath temperature of 25 ° C., a DC voltage of 150 V is applied for 3 minutes using a substrate as an anode and a stainless steel plate as a cathode to form a 15 μm thick insulating film 4 on the copper pattern circuit. did.

Next, a separately prepared acrylic / melamine resin (trade name: Hanibright CL-1, manufactured by Honey Kasei Co., Ltd.)
To 100 parts by weight, 15 parts by weight of a powder obtained by applying nickel plating to a thickness of 0.2 μm on alumina having an average particle diameter of 0.7 μm are dispersed, and the mixture of the resin and the powder is further mixed with demineralized water to obtain 1 part.
In the electrodeposition paint diluted to 5 wt%, the insulating film 4
Under the same conditions as the formation conditions, a thickness of 17
A μm conductive film 3 was formed.

Further, using the same electrodeposition paint as that for the insulating film 4, the insulating film 5 having a thickness of 15 μm was formed around the conductive film 3 under the same conditions as those for forming the insulating film 4. Finally, the substrate was washed with water. Then, put the substrate in an oven at
Heat treatment was performed for 0 minutes to obtain a circuit board of the present invention.

The physical properties (adhesion resistance, acid resistance, alkali resistance, flammability), insulation resistance and volume resistivity of the obtained circuit board were measured. The results are shown in Tables 1 to 3 below.

The obtained insulating film and conductive film were dense and sufficiently adhered to the adjacent film, and were also excellent in acid resistance, alkali resistance and combustion resistance.

Further, the measurement of the electromagnetic wave shielding effect of the circuit board was carried out by a transmission line method (ASTM ES783) after being incorporated into the product. The result is shown in FIG. The electromagnetic wave shielding effect was almost the same as the electroless plating as shown in FIG. 2 (see Reference Examples 1 and 2).

Further, the circuit board was cut as shown in FIG. 1, and a cross section of the circuit board was observed with a metal microscope manufactured by Olympus (400 times magnification). As a result, the insulating films 4, 5 and the conductive film 3 were all formed to a uniform thickness.

Reference Example 1 A copper thin film having a thickness of 0.7 μm and a film thickness of 0.4 were formed on an ABS substrate.
A μm nickel thin film was sequentially laminated by electroless plating from the ABS substrate side to obtain a metal plated member.

The measurement of the electromagnetic wave shielding effect of the metal plated member was performed in the same manner as in Example 1. The result is shown in FIG.

Reference Example 2 An ABS substrate was spray-coated with nickel powder to form a nickel coating film.

The electromagnetic wave shielding effect of the member having the nickel coating film formed thereon was measured in the same manner as in Example 1. The result is shown in FIG.

Comparative Example 1 Example 1 was formed on the same glass epoxy resin substrate as in Example 1.
After a copper pattern circuit is formed in the same manner as described above, a solder resist (trade name FINEDEL D) is formed by a conventional method.
SR-2200 (C), Tamura Seisakusho), silver paste (trade name LS-500, manufactured by Asahi Chemical Laboratory), solder resist (trade name FINEDEL DSR-2200)
(C), manufactured by Tamura Seisakusho) at 30 μm and 35 μm, respectively.
A circuit board was obtained by sequentially forming the circuit boards with thicknesses of m and 30 μm from the substrate side.

The physical properties, insulation resistance and volume resistivity of the obtained circuit board were measured in the same manner as in Example 1. The results are shown in Tables 1 to 3.

[0060]

[Table 1]

(Note) The test methods in the above table are as follows. (1) Adhesion: JIS D0202 (2) Acid resistance: Immersion treatment with 10 Vol% H ₂ SO ₄ at room temperature for 20 minutes (3) Alkali resistance: Immersion treatment with 5 wt% NaOH at room temperature for 30 minutes (4) Flammability: UL94 test method

[0062]

[Table 2]

(Note) The insulation resistance in the above table is based on JIS Z3
In accordance with 197, the comb-shaped electrode G-10 and the substrate moisture absorption treatment show a value of 1 minute at 55 ° C., 98% RH, 500 V DC.
Measurement of resistance value is made by YHP, super insulation resistance measuring instrument HP43
29A was used.

[0064]

[Table 3]

(Note) The specific resistance values in the above table are based on JIS C
6481.

Example 2 A circuit board according to the present invention was prepared in the same manner as in Example 1, except that 15 parts by weight of the nickel-plated alumina powder used in Example 1 was changed to 10 parts by weight of the copper-plated alumina powder. did. The plating thickness of the copper-plated alumina powder was 0.2 μm. The average particle diameter of the alumina powder is 1.2 μm
Met.

The physical properties (adhesion, acid resistance, alkali resistance, and flammability), insulation resistance, volume specific resistance, and electromagnetic wave shielding effect of this circuit board were measured in the same manner as in Example 1.
As a result, the same good effects as in Example 1 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 1, each film was formed to have a uniform thickness.

Example 3 A copper pattern circuit and an insulating film 4 were formed on a 0.6 mm thick glass epoxy resin substrate in the same manner as in Example 1.

Next, a separately prepared acrylic / melamine resin (trade name: Hanibright CL-1, manufactured by Hani Kasei Co., Ltd.)
To 100 parts by weight, 7 parts by weight of a powder obtained by applying a copper plating on alumina having an average particle diameter of 1.0 μm to a thickness of 0.2 μm are dispersed, and then a mixture of the resin and the powder is reduced to 15 wt% with deionized water. The conductive film 3 having a thickness of 17 μm was formed around the insulating film 4 in the diluted electrodeposition paint under the same conditions as those for forming the insulating film 4.

Finally, the substrate was washed with water, and then at 97 ° C. ±
The substrate was placed in a 1 ° C. oven and heat-treated for 150 minutes to obtain a circuit board of the present invention.

The physical properties (adhesion resistance, acid resistance, alkali resistance, and flammability) and the electromagnetic wave shielding effect of this circuit board were measured in the same manner as in Example 1. As a result, the same good effects as in Example 1 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 1, each film was formed to have a uniform thickness.

Example 4 A copper pattern circuit was formed on a 0.8 mm thick glass epoxy resin substrate in the same manner as in Example 1.

Thereafter, an alkyd resin (trade name: TF121, manufactured by Shinto Paint Co., Ltd.) having a concentration of 15 was prepared by using deionized water.
pH 8.5, bath temperature 2 using electrodeposition paint diluted to tw%
Under a condition of 5 ° C., a 150 V DC voltage was applied for 3 minutes using a stainless steel plate as a cathode with the substrate as an anode,
An m-thick insulating film 4 was formed on the copper pattern circuit.

Next, 100 parts by weight of an alkyd resin (trade name: TF121, manufactured by Shinto Paint Co., Ltd.) separately prepared was coated with nickel plating on alumina having an average particle diameter of 1.0 μm to a thickness of 0.1 μm. Disperse 7 parts by weight of the powder applied in
Further, a 17 μm thick conductive film 3 was formed around the insulating film 4 under the same conditions as those for forming the insulating film 4 in an electrodeposition paint diluted with deionized water so that the mixture of the resin and the powder became 15 wt%. Was formed.

Further, an insulating film 5 having a thickness of 15 μm was formed around the conductive film 3 using the same electrodeposition paint as the insulating film 4 under the same conditions as those for forming the insulating film 4.

Finally, the substrate was washed with water, and thereafter, at 97 ° C. ± 1.
The substrate was placed in an oven at a temperature of 150 ° C. and heat-treated for 150 minutes to obtain a circuit board of the present invention.

The physical properties (adhesion, acid resistance, alkali resistance, and flammability), insulation resistance, volume specific resistance, and electromagnetic wave shield of this circuit board were measured in the same manner as in Example 1. As a result, the same good effects as in Example 1 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 1, each film was formed to have a uniform thickness.

Example 5 A copper pattern circuit and an insulating film 4 were formed on a 0.6 mm thick glass epoxy resin substrate in the same manner as in Example 1.

Next, a separately prepared acrylic / melamine resin (trade name: Hanibright CL-1, manufactured by Hani Kasei Co., Ltd.)
100 parts by weight of copper powder 10 having an average particle diameter of 0.03 μm
Parts by weight, and the mixture of resin and powder
In the electrodeposition paint diluted to 5 wt%, the insulating film 4
Under the same conditions as the formation conditions, a thickness of 17
A μm conductive film 3 was formed.

Further, an insulating film 5 having a thickness of 15 μm was formed around the conductive film 3 under the same conditions as those for forming the insulating film 4 using the same electrodeposition paint as the insulating film 4.

Finally, the substrate was washed with water, and then at 97 ° C. ±
The substrate was placed in a 1 ° C. oven and heat-treated for 150 minutes to obtain a circuit board of the present invention.

The physical properties (adhesion resistance, acid resistance, alkali resistance, and flammability), insulation resistance, volume resistivity, and electromagnetic wave shield of this circuit board were measured in the same manner as in Example 1. As a result, the same good effects as in Example 1 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 1, each film was formed to have a uniform thickness.

Example 6 A copper pattern circuit and an insulating film 4 were formed on a 0.6 mm thick glass epoxy resin substrate in the same manner as in Example 1.

Next, a separately prepared acrylic / melamine resin (trade name: Hanibright CL-1, manufactured by Hani Kasei Co., Ltd.)
100 parts by weight of copper powder 10 having an average particle diameter of 0.02 μm
Parts by weight, and the mixture of resin and powder
In the electrodeposition paint diluted to 5 wt%, the insulating film 4
Under the same conditions as the formation conditions, a thickness of 15
A μm conductive film 3 was formed.

Finally, the substrate was washed with water, and then at 97 ° C. ±
The substrate was placed in a 1 ° C. oven and heat-treated for 150 minutes to obtain a circuit board of the present invention.

The physical properties (adhesion, acid resistance, alkali resistance, and combustibility) of this circuit board and the electromagnetic wave shielding effect were measured in the same manner as in Example 1. As a result, the same good effects as in Example 1 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 1, each film was formed to have a uniform thickness.

Example 7 A copper pattern circuit and an insulating film 4 were formed on a 0.6 mm thick glass epoxy resin substrate in the same manner as in Example 1.

Then, an alkyd resin (trade name: TF121, manufactured by Shinto Paint Co., Ltd.) having a concentration of 15 was prepared using deionized water.
pH 8.5, bath temperature 2 using electrodeposition paint diluted to tw%
Under a condition of 5 ° C., a 150 V DC voltage was applied for 3 minutes using a stainless steel plate as a cathode with the substrate as an anode,
An m-thick insulating film 4 was formed on the copper pattern circuit.

Next, 15 parts by weight of nickel powder having an average particle diameter of 0.03 μm were dispersed in 100 parts by weight of an alkyd resin (trade name: TF121, manufactured by Shinto Paint Co., Ltd.) separately prepared, and further removed. 15wt of mixture of resin and powder with salt water
% Of the conductive film 3 having a thickness of 20 μm was formed around the insulating film 4 under the same conditions as those for forming the insulating film 4 in the electrodeposition paint diluted so as to have a concentration of 10%.

Further, an insulating film 5 having a thickness of 15 μm was formed around the conductive film 3 using the same electrodeposition paint as the insulating film 4 under the same conditions as those for forming the insulating film 4.

Finally, the substrate was washed with water, and thereafter, at 97 ° C. ± 1.
The substrate was placed in an oven at a temperature of 150 ° C. and heat-treated for 150 minutes to obtain a circuit board of the present invention.

The physical properties (adhesion, acid resistance, alkali resistance, and flammability), insulation resistance, volume specific resistance, and electromagnetic wave shield of this circuit board were measured in the same manner as in Example 1. As a result, the same good effects as in Example 1 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 1, each film was formed to have a uniform thickness.

Example 8 15 parts by weight of the nickel-plated alumina powder used in Example 1 was replaced with 7 parts by weight of the nickel-plated alumina powder and 5 parts by weight of the copper powder.
A circuit board of the present invention was prepared in the same manner as in Example 1 except that the mixture was replaced by parts by weight. The plating thickness of the nickel-plated alumina powder was 0.2 μm. The average particle size of the alumina powder was 1.2 μm. The average particle size of the copper powder was 0.03 μm.

The physical properties (adhesion, acid resistance, alkali resistance, and flammability), insulation resistance, volume resistivity, and electromagnetic wave shield of this circuit board were measured in the same manner as in Example 1. As a result, the same good effects as in Example 1 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 1, each film was formed to have a uniform thickness.

Example 9 The procedure of Example 6 was repeated, except that 10 parts by weight of the copper powder used in Example 6 was changed to a mixture of 5 parts by weight of nickel-plated alumina powder and 10 parts by weight of copper powder. A circuit board of the present invention was made. The plating thickness of the nickel-plated alumina powder was 0.2 μm. The average particle size of the alumina powder was 1.0 μm. Average particle size of copper powder is 0.02μ
m.

The physical properties (adhesion resistance, acid resistance, alkali resistance, and combustibility) of this circuit board and the electromagnetic wave shielding effect were measured in the same manner as in Example 1. As a result, the same good effects as in Example 1 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 1, each film was formed to have a uniform thickness.

Example 10 Same as Example 4 except that 7 parts by weight of nickel-plated alumina powder used in Example 4 was changed to a mixture of 7 parts by weight of copper-plated alumina powder and 5 parts by weight of nickel powder. Thus, a circuit board of the present invention was prepared. The plating thickness of the copper-plated alumina powder was 0.2 μm. The average particle size of the alumina powder was 1.0 μm. The average particle size of the nickel powder was 0.03 μm.

The physical properties (adhesion, acid resistance, alkali resistance, and flammability), insulation resistance, volume resistivity, and electromagnetic wave shield of this circuit board were measured in the same manner as in Example 1. As a result, the same good effects as in Example 1 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 1, each film was formed to have a uniform thickness.

Example 11 A copper pattern circuit was formed on a 0.6 mm thick glass epoxy resin substrate in the same manner as in Example 1.

Thereafter, aluminum nitride having an average particle size of 1.5 μm was dispersed in an acrylic / melamine resin (trade name: Hanibright CL-1, manufactured by Hani Kasei Co., Ltd.) at 3% by weight of the resin, and then the resin was deionized with deionized water. Using an electrodeposition paint diluted so that the mixture of the powder and the powder becomes 15% by weight, at a pH of 8.5 and a bath temperature of 25 ° C., using a substrate as an anode, a stainless steel plate as a cathode, and 150 V Apply DC voltage for 3 minutes,
An insulating film 4 having a thickness of 15 μm and an eutectoid amount of powder of 25% by weight was formed on the copper pattern circuit.

Next, an acrylic melamine resin (trade name: Honeybright CL-1, manufactured by Honey Kasei Co., Ltd.) 1
In 100 parts by weight, 10 parts by weight of a powder obtained by applying nickel plating to a thickness of 0.1 μm on alumina having an average particle diameter of 1.0 μm is dispersed, and a mixture of the resin and the powder is further mixed with demineralized water to form a 15 w
Under the same conditions as those for forming the insulating film 4, a thickness of 17 μm
m, a conductive film 3 having an eutectoid amount of powder of 30% by weight was formed.

Further, an insulating film 5 having a thickness of 15 μm was formed around the conductive film 3 under the same conditions as those for forming the insulating film 4 using the same electrodeposition paint as the insulating film 4.

Lastly, the substrate was washed with water, and thereafter, at 97 ° C. ± 1.
The substrate was placed in an oven at a temperature of 150 ° C. and heat-treated for 150 minutes to obtain a circuit board of the present invention.

The physical properties (adhesion, acid resistance, alkali resistance, and flammability), insulation resistance, volume specific resistance, hardness (pencil) and scratch resistance (eraser) of the obtained circuit board were measured. The results are shown in Tables 4 to 6 below.

The obtained insulating film and conductive film are dense and sufficiently adhered to the adjacent film, and are resistant to acid and alkali.
The flame resistance, hardness and scratch resistance were also satisfactory.

Further, the measurement of the electromagnetic wave shielding effect of the circuit board was performed by a transmission line method (ASTM ES 7.883) after assembling into the product. As a result, the electromagnetic wave shielding effect was as good as in Example 1.

Further, when the cross section of the substrate was observed in the same manner as in Example 1, each film was formed to have a uniform thickness.

[0117]

[Table 4]

(Note) The test methods in the above table are as follows.

(1) Adhesion: JIS D0202 (2) Acid resistance: Immersion treatment with 10 Vol% H ₂ SO ₄ at room temperature for 20 minutes (3) Alkali resistance: Immersion treatment with 5 wt% NaOH at room temperature for 30 minutes (4) Flame resistance Properties: UL94 test method (5) Hardness: JIS K5400 (6) Scratch resistance: Number of times required to expose the base when rubbing the insulating coating with an eraser

[0120]

[Table 5]

(Note) The insulation resistance in the above table is based on JIS Z3
197 is compliant, and the comb-shaped electrode G-10 shows a value of 1 minute at 55 ° C., 98% RH and 500 V DC for the substrate moisture absorption treatment.
Measurement of resistance value is made by YHP, super insulation resistance measuring instrument HP43
29A was used.

[0122]

[Table 6]

(Note) The specific resistance values in the above table are based on JIS C
6481.

Example 12 Example 1 was placed on a 0.6 mm thick glass epoxy resin substrate.
A copper pattern circuit was formed in the same manner as described above.

Thereafter, 3% by weight of the aluminum nitride powder used for the insulating film 4 of Example 11 was mixed with an average particle diameter of 1.0 μm.
An insulating film 4 was formed in the same manner as in Example 11, except that the alumina powder was changed to 5% by weight.

Next, an acrylic melamine-based resin (trade name: Honeybright CL-1, manufactured by Honey Kasei Co., Ltd.) 1
15 parts by weight of a powder obtained by applying nickel plating to a thickness of 0.3 μm on alumina having an average particle diameter of 1.0 μm are dispersed in 00 parts by weight.
In the electrodeposition paint diluted to t%, under the same conditions as those for forming the insulating film 4, a thickness of 15 μm is formed around the insulating film 4.
m, a conductive film 3 having an eutectoid amount of powder of 27% by weight was formed.

Further, using the same electrodeposition paint as the insulating film 4,
An insulating film 5 having a thickness of 15 μm was formed around the conductive film 3 under the same conditions as those for forming the insulating film 4.

Finally, the substrate was washed with water, and thereafter, at 97 ° C. ± 1.
The substrate was placed in an oven at a temperature of 150 ° C. and heat-treated for 150 minutes to obtain a circuit board of the present invention.

The physical properties (adhesion resistance, acid resistance, alkali resistance, flammability, hardness and scratch resistance), insulation resistance, volume specific resistance, and electromagnetic wave shield of this circuit board were measured in the same manner as in Example 11. As a result, the same good effects as in Example 11 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 11, each film was formed to have a uniform thickness.

Example 13 A copper pattern circuit was formed on a 0.6 mm thick glass epoxy resin substrate in the same manner as in Example 1.

Thereafter, an alkyd resin (trade name: TF1)
21, manufactured by Shinto Paint Co., Ltd.), silicon carbide having an average particle size of 2.0 μm is dispersed by 1% by weight of the resin, and the mixture of the resin and the powder is adjusted to 15% by weight with demineralized water. Using the diluted electrodeposition paint, at pH 8.5 and a bath temperature of 25 ° C.,
Using a substrate as an anode and a stainless steel plate as a cathode, 15
A DC voltage of 0 V was applied for 3 minutes to form an insulating film 4 having a thickness of 15 μm and an eutectoid amount of powder of 25% by weight on the copper pattern circuit.

Next, 100 parts by weight of an alkyd-based resin (trade name: TF121, manufactured by Shinto Paint Co., Ltd.) was separately coated with copper plating on alumina having an average particle diameter of 1.0 μm and a thickness of 0.2 μm. Under the same conditions as those for forming the insulating film 4 in an electrodeposition paint diluted with 15% by weight of a resin-powder mixture with demineralized water. A conductive film 3 having a thickness of 17 μm and an eutectoid amount of powder of 30% by weight was formed around the film 4.

Further, an insulating film 5 having a thickness of 15 μm was formed around the conductive film 3 using the same electrodeposition paint as the insulating film 4 under the same conditions as those for forming the insulating film 4.

Finally, the substrate was washed with water, and thereafter, at 97 ° C. ± 1.
The substrate was placed in an oven at a temperature of 150 ° C. and heat-treated for 150 minutes to obtain a circuit board of the present invention.

The physical properties (adhesion resistance, acid resistance, alkali resistance, flammability, hardness and scratch resistance), insulation resistance, volume specific resistance, and electromagnetic wave shield of this circuit board were measured in the same manner as in Example 11. As a result, the same good effects as in Example 11 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 11, each film was formed to have a uniform thickness.

Example 14 A copper pattern circuit was formed on a 0.6 mm thick glass epoxy resin substrate in the same manner as in Example 1.

Thereafter, 3% by weight of the aluminum nitride powder used for the insulating film 4 of Example 11 was mixed with an average particle size of 5.0 μm.
Example 1 except that the alumina powder was changed to 1.5% by weight.
An insulating film 4 was formed in the same manner as in Example 1.

Next, a conductive film 3 similar to that of the eleventh embodiment was formed in the same manner as the eleventh embodiment.

Finally, the substrate was washed with water, and then at 97 ° C. ±
The substrate was placed in a 1 ° C. oven and heat-treated for 150 minutes to obtain a circuit board of the present invention.

The physical properties (adhesion resistance, acid resistance, alkali resistance, flammability, hardness and scratch resistance) of this circuit board and the electromagnetic wave shielding effect were measured in the same manner as in Example 11. As a result, the same good effects as in Example 11 were obtained.

Further, when the cross section of the substrate was observed in the same manner as in Example 11, each film was formed to have a uniform thickness.

Example 15 A copper pattern circuit and an insulating film 4 were formed on a 0.6 mm thick glass epoxy resin substrate in the same manner as in Example 1.

Thereafter, a conductive film 3 similar to that of the fifth embodiment was formed in the same manner as the fifth embodiment.

Further, the same insulating film 5 as in Example 11 was formed in the same manner as in Example 11, and finally, the film was cured in the same manner as in Example 11, thereby producing a circuit board of the present invention.

The physical properties (adhesion resistance, acid resistance, alkali resistance, flammability, hardness and scratch resistance), insulation resistance, volume specific resistance, and electromagnetic wave shield of this circuit board were measured in the same manner as in Example 11. As a result, the same good effects as in Example 11 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 11, each film was formed to have a uniform thickness.

Example 16 10 parts by weight of the nickel-plated alumina powder used in the conductive film 3 of Example 12 was mixed with silver powder 5 having an average particle diameter of 0.02 μm.
A circuit board of the present invention was prepared in the same manner as in Example 12, except that the weight part was changed.

The physical properties (adhesion resistance, acid resistance, alkali resistance, flammability, hardness and scratch resistance), insulation resistance, volume specific resistance, and electromagnetic wave shield of this circuit board were measured in the same manner as in Example 11. As a result, the same good effects as in Example 11 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 11, each film was formed to have a uniform thickness.

Example 17 A copper pattern circuit was formed on a 0.6 mm thick glass epoxy resin substrate in the same manner as in Example 1.

Thereafter, the insulating film 4, the conductive film 3, and the insulating film 5
Were formed in the same manner as in Example 11, Example 8 and Example 11, respectively, to produce a circuit board of the present invention.

The physical properties (adhesion resistance, acid resistance, alkali resistance, flammability, hardness and scratch resistance), insulation resistance, volume specific resistance, and electromagnetic wave shield of this circuit board were measured in the same manner as in Example 11. As a result, the same good effects as in Example 11 were obtained.

When the cross section of the substrate was observed in the same manner as in Example 11, each film was formed to have a uniform thickness.

[0156]

As described above, according to the present invention, the insulating film and the conductive film of the circuit board can be formed into a dense and thin film having a uniform thickness. Further, a circuit board having no insulation failure and having an excellent electromagnetic wave shielding effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a circuit board according to the present invention.

FIG. 2 is an example of a graph showing a shielding effect of a circuit board according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Conductor 3 Conductive film 4 Insulating film 5 Insulating film

Continued on the front page (31) Priority claim number Japanese Patent Application No. 2-74203 (32) Priority date Hei 2 (1990) March 24 (33) Priority claim country Japan (JP) (31) Priority claim number Special (2) Priority Date 2-77494 (32) Priority Date 2 (1990) March 26 (33) Priority Claiming Country Japan (JP) (31) Priority Claim Number Japanese Patent Application No. 2-77495 (32) Priority Date Hei 2 (1990) March 26 (33) Priority claiming country Japan (JP) Preliminary examination

Claims (4)

(57) [Claims] A first step of forming a circuit pattern made of a conductive wire on a substrate; a second step of covering the circuit pattern with a first insulating film; and forming a conductive film on the first insulating film. A third step of coating, wherein at least the third step uses an electrodeposition coating method in which the substrate is immersed in an electrodeposition coating and the conductive wire is used as an electrode. Production method. 2. The method for producing a circuit board according to claim 1, wherein in the second step and the third step, a circuit pattern is immersed in an electrodeposition paint, and an electrodeposition coating method using a conductive wire as an electrode is used. 3. A first step of forming a circuit pattern made of a conductive wire on a substrate, a second step of coating the circuit pattern with a first insulating film, and coating a conductive film on the first insulating film. In the method for manufacturing a circuit board having a third step, an electrodeposition coating method in which the substrate is immersed in an electrodeposition paint and the conductive wire is used as an electrode is applied to the second step and the third step. Forming an insulating film and a conductive film, and then curing the resin of both films. 4. A first step of forming a circuit pattern made of a conductive wire on a substrate, a second step of coating the circuit pattern with a first insulating film, and coating a conductive film on the first insulating film. A method of manufacturing a circuit board, comprising: a third step and a fourth step of covering the conductive layer with a second insulating film.
In the second step, the third step, and the fourth step, an electrodeposition coating method in which the substrate is immersed in an electrodeposition coating and the conductive wire is used as an electrode is applied to form a first insulating film. Forming a conductive film and a second insulating film, and then curing the resin of these films.