JP3098869B2 - Method for modifying resin surface, method for forming electroless plating, and small electronic circuit board manufactured using the 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 for modifying a resin surface, a method for forming electroless plating using the method, and a small electronic circuit board manufactured using the method for forming electroless plating. .

[0002]

2. Description of the Related Art At present, by using an organic substrate or an organic interlayer insulating material as a material for an electronic circuit board, it has become possible to design a circuit utilizing workability. On the other hand, heat resistance of substrate materials has been required due to miniaturization and high integration of electronic circuit substrates. In addition, demands for high-frequency dielectric properties have become stricter due to higher frequencies and general-purpose wireless communication. In particular, a substrate having a low dielectric loss has been required. As such a substrate, for example, a fluorine-based resin such as polyimide or polytetrafluoroethylene (PTFE) is used. The former is excellent in dielectric properties, heat resistance, solvent solubility, and etching properties, and the latter is excellent in dielectric properties, chemical resistance, moisture resistance, and water resistance. As the fluororesin, a resin in which a dielectric constant is controlled by mixing a filler is often used. However, these substrate materials are often poorly adhesive materials, and have poor adhesion such as plating, resist, coating materials, and adhesives.
The application was restricted. As a means for improving the adhesion of these base materials, surface modification is often used. The surface modification is mainly classified into a physical modification aiming at the anchor effect and a chemical modification modifying the chemical structure of the surface.

As a physical surface modification, there is surface roughening using a sand blast, a wire brush or the like. These methods make use of the anchor effect, and although they have some effect on polyimide, they are not sufficient, and they have no effect on fluorine-based resin such as PTFE which has strong water and oil repellency.

[0004] Chemical surface modification includes alkali treatment, acid treatment, ultraviolet treatment, corona discharge treatment, plasma treatment and the like. With respect to polyimide, a great effect can be expected depending on the application. In the case of a fluorine-based resin, a tetra-etching process, which is a kind of alkali treatment, is industrially used. Also at the research stage,
No. 9 gazettes and magazines (for example, the International Journal of Adhesion and Adhesives (INT. J. ADHESION AND ADHESIVES, Vol. 11, No. 4, No. 24)
7-254, October 1991), there is a plasma treatment under various gas atmospheres. Further, as another technique, the present inventors have proposed that a KrF excimer laser is irradiated on a PTFE surface in a glycidyl methacrylate gas atmosphere to improve the peel strength with an epoxy adhesive (1992 Polymer). (Presented at the annual conference), but it was not practically sufficient.

[0005] Further, other methods can improve the surface energy of the fluororesin, but have not yet improved the adhesion of adhesives, coatings, plating and the like.

[0006] When electroless plating is performed on a substrate having poor adhesion such as PTFE, a surface treatment must be performed to attach plating nuclei. Industrially, for example, a tetra-etching process in which a substrate is immersed in an alkaline solution as described above is performed. This method increases the polar component of the surface energy by hydrolyzing the substrate surface, thereby improving the adhesion of plating nuclei.

However, since these methods are of the wet type, the quality varies greatly, and it is difficult to selectively process only necessary portions. For example, in the case of the full additive method, after nucleation, resist coating, patterning, and electroless plating are performed. However, nuclei remaining between the patterns adversely affect insulation because nuclei are formed on the entire surface.

[0008]

Therefore, it is possible to selectively modify the surface of only the required portions without being affected by the shape of the resin base material, and to have excellent adhesion to adhesives, coating agents, plating and the like. There is a need for a method of modifying the resin surface. In addition, when performing electroless plating, there is a demand for an electroless plating method that does not leave plating nuclei between patterns and does not affect insulation. An object of the present invention is to solve the conventional problems as described above.

[0009]

Means for Solving the Problems As a result of intensive studies, the present inventors were able to solve the above-mentioned conventional problems. That is, the first aspect of the present invention is that, under an atmosphere of an amine compound gas and / or an amide compound gas, an ultraviolet laser having a main wavelength component of 360 nm or less is applied to a resin substrate for 30 m.
J / cm ² · pulse ~1J / cm ² · pulse energy of
An object of the present invention is to provide a method for modifying a resin surface, which comprises irradiating at a density .

In the second aspect of the present invention, the surface of only a required portion of the resin surface is modified by the method described above, and plating nuclei are selectively adhered only to the surface-modified portion. An object of the present invention is to provide a method for forming electroless plating, in which generation and patterning of electrolytic plating are simultaneously performed.

A third aspect of the present invention is the second aspect of the present invention.
The present invention provides a small-sized electronic circuit board manufactured by a manufacturing process including an electroless plating forming process of the method described in (1).

Hereinafter, the present invention will be described in more detail. The resin surface modification method of the present invention comprises irradiating an excimer laser beam to the surface of a resin substrate in an atmosphere of an amine compound gas and / or an amide compound gas, modifying only the irradiated portion of the resin surface, forming an adhesive, It significantly improves the adhesion to materials, plating and the like. Furthermore, when only the necessary portions are surface-modified by this method and electroless plating is applied, only the surface-modified portions are nucleated and the electroless plating pattern is formed directly, so the pattern between the patterns caused by the remaining plating nuclei is formed. Insulation deterioration can be eliminated.

The resin substrate that can be used in the present invention is not particularly limited as long as it is an organic polymer compound. In particular, a fluorine-based polymer such as PTFE or polyvinylidene fluoride, a liquid crystal polymer, a polyolefin-based polymer such as polyethylene, and a polyimide have not been able to obtain a sufficient surface-modifying effect by the conventional method. , Practical adhesion to an adhesive or plating can be obtained. Note that, for example, polyethylene terephthalate, polyparaphenylsulfone, and the like can be surface-modified with a practical effect even using a low-wavelength component of a low-pressure mercury lamp, and there is little merit of using a laser as a light source.

The amine compound or amide compound used in the present invention preferably has a molecular weight of 500 or less. When the molecular weight exceeds 500, gasification is difficult. Further, amine or amide compounds having a photopolymerizable unsaturated group in the molecule are preferred because they have a large effect because they are efficiently grafted to the resin surface. Specifically, acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropylacrylamide, N, N-isopropylacrylamide, acryloyl morpholine, vinylpyrrolidone, vinylpyridine, vinylaniline, Vinylimidazole,
Vinyl pyrazine is preferred.

The ultraviolet laser having a main wavelength component of 360 nm or less according to the present invention is, specifically, F ₂ (157n).
m), ArF (193 nm), KrCl (222n)
m), KrF (248 nm), XeCl (308 n
m), an excimer laser of XeF (351 nm) is preferable. In particular, ArF and KrF are preferable because they have good light source stability and a large surface modification effect. The energy per pulse is preferably from 1 J / cm ² to 1 mJ / cm ² , and if it exceeds this, the ablation effect is too strong, damaging the resin or removing even amine compounds attached or covalently bonded to the resin surface. Resulting in. On the other hand, if it is less than this, the energy is insufficient and the resin surface cannot be modified.

The amide compound gas and / or amine compound gas used in the present invention can be introduced so that the degree of vacuum in the chamber for irradiating the laser beam is in a proper range from 1 mTorr to normal pressure. That is, the selection may be made according to the respective boiling points of the amide compound gas or amine compound gas used. However, a high vacuum of less than 1 mTorr is not preferable because the degree of contact between the resin and the amide compound gas or the amine compound gas becomes poor. Also,
The gas is preferably introduced forcibly into the chamber with an inert gas such as argon gas.
When the amide compound gas and the amine compound gas are used as a mixture, the ratio between the two is not particularly limited and can be freely selected.

As described above, the resin substrate is preferably placed under reduced pressure or an inert gas atmosphere. This is to stabilize radicals generated when a laser is irradiated to the resin and the amide compound gas and / or the amine compound gas, and to promote covalent bonding between the amide or amine compound gas and the resin. Further, under reduced pressure, a compound that is a liquid at room temperature is also easily gasified, which is preferable.

When the resin surface is modified by electroless plating using the resin surface modification method of the present invention, and the patterning is formed at the same time, when the surface of the substrate is modified, the distance between the laser light source and the resin is reduced. Then, a mask is inserted, only the necessary portions are modified, and then the conventional electroless plating can be applied. The plating nuclei adhere only to the modified surface of the substrate, resulting in a patterned and deposited plating. At this time, it is necessary to select a mask base material having good laser light transmittance, and synthetic quartz or the like is preferable.

The resin substrate to which the method of the present invention is applied is preferably a small substrate having a unit size of 1000 cm ² or less, for example. Originally the laser beam was 10mm x 50
Although it is about mm square, the laser light used in the resin surface modification method of the present invention can be used although relatively low energy can be used, so the laser light irradiation area can be expanded by using a lens. It is. However, an excessively large substrate is not effective in consideration of a laser irradiation area.

FIG. 1 shows an example of an apparatus for performing the method of the present invention.
Shown in Chamber 3 is 1 mTorr ~ by vacuum pump 5
Adjusted to normal pressure. Also, an amide or amine compound 8
Is filled in the container 7. Ar gas from the Ar cylinder 11 enters the container 7 while being adjusted by the mass flow meter 10 as an inert gas. The amide or amine compound enters the chamber 3 together with Ar gas through the opened cock 4 by using a heating means (not shown) if necessary. The resin substrate is irradiated with the laser beam 1 through the quartz window 2 on the chamber 3 under an amide or amine compound gas atmosphere. Although not shown, when using a mixed gas of an amine compound and an amide compound,
For example, the containers 7 can be arranged in parallel, and Ar gas can be injected into each of the containers 7 to simultaneously fill the chamber 3. When an amide or amine compound having a high boiling point is used, heating from the container 7 to the chamber 3 may be performed.

[0021]

According to the method for modifying a resin surface of the present invention, a laser beam having a specific wavelength is irradiated to form a covalent bond between the resin surface and an amide or amine compound gas, and the resin surface and the adhesive or Good adhesion to plating and the like. In this method for modifying the resin surface, a laser beam is used, so that the surface modification can be performed only on a necessary portion without being affected by the shape of the resin base material. Therefore, electroless plating having good adhesion can be formed without performing special pretreatment.

[0022]

The present invention will be described below with reference to examples. Embodiment 1 FIG. In a chamber 3 of the apparatus shown in FIG. 1, PTFE having a thickness of 200 μm and a size of 50 × 50 mm square was used as a sample.
The film was put in, and the pressure was reduced to 10 mTorr. Next, the cock of the container 7 containing dimethylaminoethyl acrylate was opened, and 100 sccm of Ar gas was flowed into the container as a carrier gas. The pressure in the chamber at that time is 10
It was 0 mTorr. Next, a KrF excimer laser is applied for 1 cm.
After irradiating the sample surface through a quartz window for 7 minutes under the conditions of × 3 cm square shape, 62 mJ / cm ² · pulse, pulse width 10 ns, and frequency 10 Hz, the cock of the container 7 was closed,
After leaking the inside of the chamber with nitrogen gas, a sample was taken out. Of the sample surface taken out,
It was slightly yellow and dark. Two samples were prepared, and a strip test piece of 1 cm × 10 cm including an irradiated surface was prepared for a peeling test, and the irradiated surface was bonded with an epoxy-based adhesive Araldide Standard (manufactured by Ciba Geigy). The curing condition at this time was 2 days at room temperature. The peel test piece thus obtained is referred to as test piece 1.

The sample obtained above was used as a plating nucleating agent, Activator Neogant (manufactured by Nippon Schering Co., Ltd.).
5 minutes at room temperature, washed with water, immersed in activator reducer Neogant (manufactured by Nippon Schering) for 5 minutes, and air-stirred at 45 ° C. in electroless copper plating solution enplate Cu704 (manufactured by Meltex). When immersed for 4 hours in the lower part, copper plating having a thickness of about 18 μm was formed only in the portion irradiated with the laser beam. This sample is similarly 1 cm x 10 cm
Was cut into strips, and a copper / PTFE peel test piece was obtained. The test piece thus obtained is referred to as test piece 2.

A PT of 30 mm × 80 mm square and 1 mm thick
Place the FE substrate in the chamber under the same conditions as above,
mJ / cm ² pulse, 10 ns, 10 Hz, irradiation area 2.
5cm x 7.5cm square KrF excimer laser light
The PTFE surface was irradiated through a 100 μm line and space quartz / chrome mask for a minute. The obtained sample was immersed in a plating nucleating agent Activator Neogant (manufactured by Nippon Schering) for 5 minutes at room temperature, washed with water, and then immersed in activator reducer Neogant (manufactured by Nippon Schering) for 5 minutes. When immersed in an electroless copper plating solution enplate Cu704 (manufactured by Meltex Corporation) at 45 ° C. for 4 hours under air agitation, Cu plating having a thickness of about 18 μm was formed only in the portion irradiated with the laser beam. The pattern width obtained at this time was about 110 μm. Further, the comb-shaped test pattern shown in FIG. 2 was formed by the same process. This comb-shaped test pattern is referred to as a test piece 3.

Embodiment 2 FIG. A 50 μm-thick, 50 × 50 mm square polyimide film Kapton (manufactured by DuPont) is placed in the chamber of the apparatus shown in FIG.
The pressure was reduced to rr. Next, the cock of the container containing dimethylaminoethyl acrylate was opened, and Ar gas (100 sccm) was flowed into the container as a carrier gas. The pressure in the chamber at that time was 100 mTorr. Next, Kr
F excimer laser is 1cm x 3cm square, 40mJ
/ Cm ² · pulse, pulse width 10 ns, frequency 10 Hz
After irradiating the sample surface through a quartz window for 7 minutes, the cock of the container was closed, the inside of the chamber was leaked with nitrogen gas, and then the sample was taken out. Of the sample surface taken out,
Only the irradiated part was darkened. Two pieces of this sample were prepared, and a strip test piece of 1 cm × 10 cm including the irradiated surface was cut out for a peel test, and the irradiated surface was bonded with an epoxy-based adhesive Araldide Standard (manufactured by Ciba Geigy). The curing condition at this time was 2 days at room temperature. The peel test piece thus obtained is referred to as test piece 4.

Next, a polyimide film Kapton (manufactured by DuPont) having a thickness of 50 μm, 5.0 × 7.5 cm square, and a thickness of 30 m
J / cm ² pulse, pulse width 10 ns, frequency 10H
z, using a KrF excimer laser beam having an irradiation area of 2.5 cm × 7.5 cm square under the same chamber conditions as above, the sample was treated with a plating nucleating agent Activator Neogant (manufactured by Nippon Schering Co., Ltd.) at room temperature. For 5 minutes, rinse with water, immerse in activator reducer Neogant (manufactured by Nippon Schering Corporation) for 5 minutes, and in an electroless copper plating solution enplate Cu704 (manufactured by Meltex) at 45 ° C. under air stirring. When immersed for 4 hours, copper plating having a thickness of about 18 μm was formed only at the portion irradiated with the laser beam. This sample was similarly cut into 1 cm × 10 cm strips to obtain copper / Kapton peel test specimens. The test piece thus obtained is referred to as test piece 5.

Also, 30 mm × 80 mm square, thickness 100 μm
Is placed in a chamber under the same conditions as above, 30 mJ / cm ² pulse, pulse width 10 ns, frequency 10 Hz, irradiation area 2.5 cm × 7.5 cm
The KrF excimer laser beam at the corner is irradiated with 100 μm for 10 minutes.
The PTFE surface was irradiated through an m-line and space quartz / chrome mask. The obtained sample was immersed in a plating nucleating agent Activator Neogant (manufactured by Nippon Schering) for 5 minutes at room temperature, washed with water, and then immersed in activator reducer Neogant (manufactured by Nippon Schering) for 5 minutes. When immersed in an electroless copper plating solution enplate Cu704 (manufactured by Meltex Corporation) at 45 ° C. for 4 hours under air stirring, only a portion irradiated with laser light was about 18 μm.
Thick copper plating was formed. The pattern width obtained at this time was about 115 μm. Further, the comb-shaped test pattern shown in FIG. 2 was formed by the same process. This comb-shaped test pattern is referred to as a test piece 6.

Embodiment 3 FIG. In the chamber, as a sample,
GTL-800 0.635mm thick, 50mm x 75mm square
No. 0 substrate (Gore-Tex Japan Co., Ltd. high-frequency substrate (fluorine-based substrate)) without copper paste is inserted, and the inside is 10 mTorr
The pressure was reduced to Next, open the cock of the container containing dimethylaminoethyl acrylate, and use A as a carrier gas.
100 sccm of r gas was flowed into the container, and the pressure in the chamber was set to 100 mTorr. Next, the sample surface was irradiated with a KrF excimer laser through a quartz window for 7 minutes under conditions of 62 mJ / cm ² pulse, pulse width of 10 ns, and frequency of 10 Hz, and the entire surface was surface-modified. Subsequently, the obtained sample was adhered to the center of a copper-clad laminate epoxy resin substrate FR-4 having a size of 5.5 cm × 8.0 cm and a thickness of 2 mm using an adhesive. Next, the same surface treatment as described above was performed on the GTL-8000 surface opposite to the side to be pasted through a quartz / chrome mask, and the protruding copper portion was masked with tape, and described in Example 1. When an electroless plating process was performed by the above process, a copper plating circuit pattern having a thickness of 18 μm was formed without etching. Subsequently, the above surface modification was performed on the entire surface of the copper plating circuit pattern.

A punch hole of 0.5 mm in diameter was punched in a predetermined position of another GTL-8000 sheet with a punch, and one surface of the sheet was subjected to the same surface modification as described above, and further aligned to form the above. Glued on the copper pattern. Next, perform surface modification through a mask as described above,
An electroless copper plating pattern was formed to obtain a two-layer substrate.
The substrate thus obtained was heated at 150 ° C./1 hour to 30 ° C./1.
The heat shock test for 100 hours was performed for 100 hours.
Defects such as peeling of conductors and interlayers, poor connection of the buyer hole, and cracking of the substrate were not observed.

Embodiment 4 FIG. In the chamber, as a sample,
BT resin substrate (without copper paste)
The pressure was reduced to Next, open the cock of the container containing dimethylaminoethyl acrylate, and use A as a carrier gas.
100 sccm of r gas was flowed into the container. The pressure in the chamber at that time was 100 mTorr. Next, a KrF excimer laser was pulsed at 62 mJ / cm ² · pulse, pulse width 1
0 ns at a frequency of 10 Hz for 7 minutes through a mask
Irradiation with an rF laser was performed to modify the surface of the portion requiring plating. Next, it was immersed in an activator neogant at room temperature for 5 minutes to attach a plating nucleus to the modified portion. A photosensitive permanent resist dry film PHOTEC was stuck on the processed surface side of this sample, and patterning was performed so that the surface-treated portion was exposed. This sample was immersed in a plating nucleating agent, Reducer Neogant for 5 minutes at room temperature to activate the plating nucleus.
After washing with water, it was immersed in an enplate Cu704D at 45 ° C. for 5 hours with air stirring to obtain a copper plating pattern of about 18 μm. As a test pattern, a comb-shaped electrode pattern having a space of 2 mm shown in FIG. 2 was produced by the same process. This is designated as test piece 7.

Evaluation Results The peel strength results of the test pieces 1 (PTFE), test piece 4 (polyimide film) and comparative test pieces using the same adhesive as in Example 1 are shown below. In addition, the comparative test piece
Untreated PTFE (comparative test piece 1), tetra-etch treatment (comparative test piece 2), untreated Kapton film (comparative test piece 3), 650W low-pressure mercury lamp 30-second irradiated Kapton film (comparative test piece 4), and tested simultaneously did. The crosshead speed (peeling speed) was 10 cm / min. Table 1 shows the results.

[0032]

[Table 1]

The results of the peeling test between the test piece 2 (PTFE), the test piece 5 (polyimide film) and the comparative test piece and the electroless copper plating are shown below. The comparative test pieces were untreated PTFE (comparative test piece 5), tetra-etched treatment (comparative test piece 6), untreated Kapton film (comparative test piece 7), 650 W low-pressure mercury lamp 30-second irradiated Kapton film (comparative test piece). 8), and each was tested simultaneously. However, since the plating nucleus does not adhere to the comparative test piece 7 as it is, as a general pretreatment, the securigant 9 is used.
02 (Nippon Schering Co., Ltd. degreasing detergent) for 5 minutes at room temperature, hot water washing, immersion in Neutra Gantt (Nippon Schering Co., Ltd. surface roughening agent) for 5 minutes at room temperature, hot water washing, Predip Neo Gantt (Nippon Schering Co., Ltd.) (Neutralizing treatment agent) was used after being immersed in a room temperature for 1 minute and washed with hot water. Peeling test conditions were the same as above. Table 2 shows the obtained results.

[0034]

[Table 2]

The results of Tables 1 and 2 clearly show the effectiveness of the method of the present invention.

Next, the insulation properties between the copper plating patterns of the test piece 3, the test piece 6, the test piece 7, and the comparative test piece were evaluated. The comb-shaped electrode of each test piece was placed in an environment of 50 ° C. and 90% relative humidity, DC45V was applied to both ends, and the current value after 24 hours was measured. The comparative test piece was a sample in which electroless copper plating was formed by 18 μm on the entire surface of a 1 mm thick PTFE substrate which had been subjected to tetraetching, and the same pattern as that of the test piece 3 was formed by etching using an etching resist and ferric chloride. (Comparative test piece 9), 50 μm in the same manner
A sample having a pattern formed on a thick Kapton film (comparative test piece 10) and a BT resin substrate (without copper coating) dipped in Securigant 902 (a degreasing cleaning agent manufactured by Nippon Schering Co., Ltd.) for 5 minutes at room temperature, washed with hot water, and neutralized. Immerse in Gantt (Nippon Schering Co., Ltd. surface roughening agent) for 5 minutes at room temperature, wash with hot water, pre-dip neogant (Nippon Schering Co., Ltd., neutralizing agent) for 1 minute at room temperature, wash with hot water, and then activate Immerse in Neo Gantt for 5 minutes at room temperature to attach plating nuclei to the modified part, apply photosensitive permanent resist dry film Photech on the processed surface side of this sample, perform the same patterning as sample piece 7, and perform reducer Neogant 5 minutes at room temperature to activate the plating nucleus. After washing with water, the plate was immersed in an emplate Cu704D at 45 ° C. for 5 hours with air stirring. Those obtained copper plating pattern of μm was (comparative test piece 11). Table 3 shows the obtained results.

[0037]

[Table 3]

As described above, the test piece 3, the comparative test piece 9,
There is almost no difference between the test piece 6 and the comparative test piece 10, which indicates that the copper wiring produced by the method of the present invention has almost the same performance as the conventional one. Furthermore, when applied to the full additive method, it can be seen that the test piece 7 of the test piece 7 and the comparative test piece 11 has better inter-wiring insulation characteristics. This is considered to be due to the fact that no plating nuclei were attached between the wires in the test piece 7.

[0039]

According to the present invention, it is possible to selectively modify the surface of only a required portion without being influenced by the shape of the resin substrate, and to modify the resin surface having excellent adhesion to an adhesive or plating. A method is provided. Further according to the invention,
Provided is a method for forming electroless plating in which plating nuclei do not remain between patterns and do not affect insulation. When the method of the present invention is applied to a plating patterning process, electroless plating can be deposited directly on a substrate in a pattern, and a multilayer substrate can be manufactured without an etching process by applying the method to electronic circuit board manufacturing.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of a surface modification device used in the present invention.

FIG. 2 is a schematic diagram of a comb-shaped test pattern.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser light 2 Quartz window 3 Chamber 4 Cock 5 Vacuum pump 6 Vacuum gauge 7 Container 8 Amide or amine compound 9 Flow meter 10 Mass flow meter 11 Ar cylinder

Claims (5)

(57) [Claims] 1. A resin base material having a main wavelength component of 360% under an atmosphere of an amine compound gas and / or an amide compound gas.
the ultraviolet laser is nm or less 30mJ / cm ² · Pa
A method for modifying a resin surface, comprising irradiating with an energy density of 1 to ¹ J / cm ² · pulse . 2. An amine compound gas and / or amide.
The compound gas has a molecular weight of 500 or less and has a light weight in the molecule.
Characterized by having a compatible unsaturated group.
The method for modifying a resin surface according to claim 1. 3. A resin base material comprising a fluoropolymer and a poly
3. The resin table according to claim 1, which is selected from imides.
Surface modification method. 4. A method according to claim 1 , wherein only a required portion of the resin surface is surface-modified, and plating nuclei are selectively adhered only to the surface-modified portion. Method for forming and patterning electroless plating at the same time. 5. The method according to claim 4 , which is manufactured by a manufacturing process including an electroless plating forming process.
Small electronic circuit board.