JP2013234345A - Plating method and plating wiring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plating method capable of forming a conductor film excellent in adhesion on a smooth electrical insulation substrate, not needing a highly heat resistant substrate, using inexpensive materials, and not installing a complex process such as modification of a substrate surface.SOLUTION: A plating method for forming a conductor film on a surface of an electrical insulation substrate includes: a coating film formation process for spreading a coating composition that contains metal particulates that is to be growth nuclei of plating and a binder that has adhesiveness to the surface of the substrate to form a coating film; a plasma treatment process for decomposing and removing organic components near the surface of the coating film by vacuum plasma to make the metal particulates expose to the surface of the coating film, and activating the exposed metal particulates; an electroless plating process for applying electroless plating to the plasma-treated surface of the coating film to form an electroless plating coating; and an electroplating process for applying electroplating to the surface of the electroless plating coating to develop the electroplating coating to a prescribed thickness.

Description

  The present invention is a plating method for forming a conductive film having excellent adhesion on a smooth electrical insulating substrate used for a printed circuit board and the like, and a smooth electrical insulating substrate formed using the plating method. The present invention relates to a plated wiring having excellent adhesion.

  Wiring boards for electronic devices and semiconductor devices are manufactured by providing a conductive film such as copper in close contact with the surface of a smooth board made of an electrically insulating resin such as polyimide resin or epoxy resin. When such a conductor film is provided using a plating method, the substrate is electrically insulating as described above, and therefore the conductor film cannot be formed as it is. Therefore, first, after electroless plating is performed on the surface of the resin substrate to form a thin electroless plating film, a conductor layer is provided, and then the electroless plating film surface is electroplated to a predetermined thickness. A conductor film is formed by growing an electrolytic plating film.

  In the formation of such a conductor film, an electroless plating film, which is a resin substrate and a conductor layer, has conventionally been produced by performing an etching process or the like on the resin substrate to form a fine irregular surface on the surface, thereby producing an anchor effect. The adhesion of the layers was ensured, and an electroplating film layer was formed on the electroless plating film layer to form a conductor film.

  This conventional method for forming a conductor film will be described with reference to FIG. 3, taking as an example a case where a copper plating film is formed as a conductor film on a resin substrate.

(A) Degreasing step First, as shown in FIG. 3 (a), in order to improve wettability during etching, the resin substrate is degreased to remove oil and fat, dirt, and the like attached to the surface. .

(B) Etching Step Next, as shown in FIG. 3B, the resin substrate surface is roughened by chemically treating it with chromic acid or the like to form unevenness of several μm level on the surface of the resin substrate. Let The unevenness serves as an anchor to ensure the adhesion between the electroless copper plating film and the resin substrate. After the etching is completed, the substrate surface is cleaned using hydrochloric acid or the like to remove the remaining chromium compound.

(C) Catalyst Step Next, as shown in FIG. 3 (c), on the surface of the roughened resin substrate, a Pd compound (generally, a catalyst metal that becomes the core of electroless copper plating) Pd—Sn complex is used).

(D) Accelerator Step Next, as shown in FIG. 3D, after dissolving this compound, metal Pd particles are generated on the surface of the resin substrate by an oxidation-reduction reaction. After completion of the accelerator, the substrate surface is washed with water to remove Sn separated from Pd.

(E) Electroless Copper Plating Step Next, as shown in FIG. 3E, electroless copper plating is performed on the surface of the resin substrate (electroless copper plating treatment). At this time, copper ions are reduced by the catalytic activity effect of the metal Pd, and an electroless copper plating film having a thickness of 1 to 2 μm is formed on the surface of the resin substrate. Since the electroless copper plating film is also formed in the irregularities, adhesion with the substrate is ensured.

(F) Electrolytic copper plating step Finally, as shown in FIG. 3 (f), an electrolytic copper plating film is grown to a predetermined thickness on the surface of the electroless copper plating film by the electrolytic copper plating process, Finish formation.

  However, in the conventional method for forming a conductive film, in addition to the above-described steps, it is necessary to separately provide a step of removing a chromium compound, a step of removing Sn, and the like. I need. Further, the removed chromium compound and Sn cannot be discharged as they are, and there is a problem that the environmental load is high.

  Furthermore, in recent years, there has been an increasing demand from users for downsizing and high performance of electronic devices and semiconductor devices, and the provision of a wiring board capable of high-speed transmission (high frequency) of electrical signals is strongly desired. However, in the substrate manufactured by the above method, since the unevenness formed by etching acts as an antenna, it may cause noise oscillation and hinder high-speed transmission. In the case of a multilayer substrate, There was also a risk of causing a discharge short for another layer.

  For these reasons, various techniques for forming a conductor film having excellent adhesion to a substrate without providing an uneven anchor by etching or the like have been studied.

  For example, a technique has been proposed in which copper nano ink is applied onto a substrate and a plating pattern is formed thereon to form a conductor film (Non-patent Document 1). However, in the case of this technique, the conductive film cannot be formed unless the oxide film formed on the surface of the copper nanoparticles is removed and the particles are melted. Therefore, there is a problem that a substrate having high heat resistance must be used.

  In addition, a technique has been proposed in which a conductive film is formed by applying a silver nanoparticle paste onto a substrate and curing it to form a conductive film (Patent Document 1). However, in the case of this technique, since silver nanoparticles are expensive, there is a problem that an increase in cost cannot be avoided.

  In addition, a technology has been proposed in which a conductive pattern is formed by forming a conductive pattern by modifying the surface of the substrate by introducing a hydrophilic functional group on the substrate surface and applying copper ink or the like thereon. (Patent Document 2). However, in the case of this technique, it is necessary to provide a process for modifying the substrate surface in advance, and there is a problem that the process becomes complicated.

JP 2009-136037 A JP 2010-156022 A

Catalog “Photosintering Type Conductive Copper Nano Ink”, Ishihara Pharmaceutical Co., Ltd., April 2011

  In view of the above, the present invention does not require a substrate having high heat resistance, and does not require a complicated process such as modifying the substrate surface with an inexpensive material, thereby providing adhesion on a smooth electrically insulating substrate. It is an object of the present invention to provide a plating method capable of forming an excellent conductor film.

  As a result of intensive studies, the present inventor has found that the above problems can be solved by the invention shown below, and has completed the present invention. Hereinafter, each claim will be described.

The invention described in claim 1
A plating method for forming a conductor film on the surface of an electrically insulating substrate,
On the surface of the substrate, a coating composition is formed by applying a coating composition containing fine metal particles serving as a growth nucleus of plating and a binder having adhesiveness to the substrate, and forming a coating film,
A plasma treatment step of decomposing and removing organic components near the surface of the coating film by vacuum plasma to expose the metal fine particles on the surface of the coating film and activating the exposed metal fine particles;
Electroless plating is performed on the surface of the plasma-treated coating film to form an electroless plating film; and
An electroplating step of performing electroplating on the surface of the electroless plating film to grow the electroplating film to a predetermined thickness.

  In the invention of this claim, since the coating composition contains a binder having adhesiveness to the substrate, the coating film exhibits sufficient adhesion to a smooth substrate. And by vacuum plasma treatment, organic components near the surface of the coating are decomposed and removed to expose the fine metal particles that are the growth nuclei of the plating to the surface of the coating and to activate the exposed fine metal particles. The electroless plating film grown with metal fine particles as the core exhibits sufficient adhesion to the coating film. As a result, the conductor films (electroless plating film and electrolytic plating film) are sufficiently adhered to the smooth substrate through the coating film to form a conductor film having excellent adhesion on the smooth electrically insulating substrate. be able to.

  In addition to the above-mentioned vacuum plasma treatment, UV treatment can be considered as a method of coating film treatment. However, UV treatment is preferable because it has a problem that the decomposition and removal ability of organic components is low and metal fine particles cannot be exposed. Absent.

  As described above, according to the present invention, a conductive film having excellent adhesion can be formed on a smooth electrically insulating substrate. There is no fear of disturbing transmission. Further, even in the case of a laminated substrate, there is no possibility of causing a discharge short circuit with respect to another layer.

  According to the invention of this claim, since curing and annealing at a high temperature are not required, a substrate having high heat resistance is not required. Further, since the conductor film can be formed with an inexpensive copper plating film or the like, it is not necessary to use an expensive silver nanopaste or the like. Furthermore, it is not necessary to provide a complicated process such as modifying the substrate surface.

  A dispersant may be added to the coating composition in order to further improve the dispersibility of the metal fine particles. Moreover, in order to make application | coating to a board | substrate easy, you may add a solvent as a viscosity modifier.

The invention described in claim 2
The gas to be plasmified in the plasma treatment step is one or more selected from O ₂ , O ₃ , N ₂ , H ₂ , Ar, He, H ₂ O, CF ₄ , CHF ₃ , CO, and CO _2. The plating method according to claim 1, wherein the plating method is provided.

  By performing vacuum plasma treatment using these gases, it becomes possible to reliably decompose and remove organic components near the surface of the coating film and to activate the metal fine particles.

  These gases are appropriately selected in consideration of the substrate material, the composition of the coating composition, the plating material, and the like.

The invention according to claim 3
3. The plating method according to claim 1, wherein the plasma treatment is a vacuum plasma treatment performed under conditions of a pressure of 1 to 1000 Pa and a frequency of 1 to 1000 MHz.

  By performing vacuum plasma treatment under conditions of a pressure of 1 to 1000 Pa and a frequency of 1 to 1000 MHz, it is possible to reliably perform decomposition and removal of organic components and activation of metal fine particles even at a temperature of 100 ° C. or lower. . For this reason, it is not necessary to provide a high temperature treatment facility. Moreover, the board | substrate generally used conventionally from which it cannot be said that heat resistance is high can be used as a board | substrate. As a result, it is preferable without causing an increase in cost.

  In addition, if the plasma recipe such as the kind of gas and plasma conditions described above is changed as appropriate and the vacuum plasma treatment is a continuous step treatment, the metal fine particles are sufficiently removed after the organic component is sufficiently decomposed and removed. It is more preferable because it can be activated.

The invention according to claim 4
Prior to the coating film forming step, the substrate is provided with a plasma processing step of performing atmospheric plasma processing on the substrate under conditions of a pressure of 0.1 ± 0.01 MPa and a frequency of 1 to 100 kHz. 4. The plating method according to any one of 3 above.

  Prior to the formation of the coating film, by subjecting the substrate to atmospheric plasma treatment, the hydrophilicity, lipophilicity and adhesiveness of the substrate surface are improved, and a coating film with better adhesion can be formed.

The invention described in claim 5
The substrate is epoxy resin, polyimide, polypropylene, polyethylene terephthalate, polyethylene, polystyrene, acrylic resin, polyvinyl chloride, polyvinyl acetate, fluororesin, ABS resin, AS resin, phenol resin, melamine resin, polyester, polyurethane, urea resin 5. The plating method according to claim 1, wherein the main component is one or more selected from alkyd resins.

  A substrate containing these materials as a main component has a low dielectric constant, and is conventionally used as a high-frequency substrate material, so that it does not cause an increase in cost.

  If the substrate is too thin, the strength is insufficient. On the other hand, if the substrate is too thick, the volume and weight of the electronic substrate are increased, which is inappropriate. For this reason, the thickness of the substrate is preferably about 0.1 to 5 mm, and more preferably about 0.2 to 1 mm.

  In addition, "it is as a main component" shows that these materials are contained more than 50%, and other materials may be contained in a small amount. Further, the substrate is not limited to a single layer, and may be configured to be laminated from the viewpoints of bending strength, cost, compactness, and high wiring density. Specifically, for example, a substrate in which a film of these materials is laminated on the surface of a general plating base such as a glass epoxy base can be exemplified.

The invention described in claim 6
The metal fine particles are
The main component is a single metal selected from Pt, Pd, Ni, Cu, Ti, V, Mn, Fe, Co, Ag, Au, or an alloy composed of two or more metals.
6. The plating method according to claim 1, wherein the particle diameter is a metal fine particle having a particle diameter of 1 nm to 1 mm.

  Since these metal fine particles are reduced by the vacuum plasma treatment and the surface is sufficiently activated, the catalytic activity as a growth nucleus of plating in electroless plating can be sufficiently exerted, and more sufficiently An electroless plating film can be formed with excellent adhesion.

  If the particle size is too small, it becomes difficult to be shaped into particles at the atomic level. On the other hand, if it is too large, it becomes impossible to mix and disperse into the material. More preferably.

The invention described in claim 7
The binder according to any one of claims 1 to 6, wherein the binder is mainly composed of one or more selected from acrylic, urethane, hexane, styrene, benzene, ethers, and acetic acid organic compounds. The plating method described.

  These binders are preferable because they are relatively inexpensive and have sufficient adhesion to the above-described substrates.

The invention according to claim 8 provides:
A plated wiring formed by processing a conductor film formed on a smooth electrically insulating substrate using the plating method according to claim 1. is there.

  Since the conductor film formed on the smooth electrically insulating substrate using each of the above plating methods has excellent adhesion to the substrate, the conductor film is excellent by forming a wiring circuit by processing means such as etching. A plated wiring having excellent adhesion can be provided.

  According to the present invention, a substrate having high heat resistance is not required, and it is excellent in adhesiveness on a smooth electrically insulating substrate without providing a complicated process such as modifying the substrate surface with an inexpensive material. A plating method capable of forming a conductor film can be provided. Moreover, the plated wiring which has the outstanding adhesiveness can be provided.

It is a figure explaining the plating method in one embodiment of the present invention. It is a figure which shows typically the structure of the plasma processing apparatus used by one embodiment of this invention. It is a figure explaining the formation method of the conventional conductor film.

  Hereinafter, the present invention will be specifically described based on embodiments.

  FIG. 1 is a diagram for explaining a plating method in the present embodiment, and a plating film is formed through the steps (a) to (f). In FIG. 1, 10 is a substrate, 11 is a base material, 12 is a resin film, 13 is a coating film, 14 is a metal fine particle, 15 is an electroless plating film, and 16 is an electrolytic plating film. Hereinafter, it demonstrates in order of a process.

1. Preparation of substrate First, a substrate 10 on which a plating film is to be formed is prepared. As the substrate 10, a substrate made of each material described above can be used. As shown in FIG. 1A, these materials are combined to form a substrate 10 on which a base material 11 and a resin film 12 are laminated. Is preferably used.

  In addition, the substrate 10 is degreased in the same manner as in the past to remove oils and fats and dirt adhering to the surface, but if necessary, pressure 0.1 ± 0.01 MPa, frequency 1-100 kHz Atmospheric plasma treatment may be performed under conditions. The treatment time is preferably about 1 to 5 minutes. Thereby, as described above, the hydrophilicity, lipophilicity, and adhesiveness of the substrate surface are improved, and a coating film with more excellent adhesion can be formed.

2. Formation of Coating Film (1) Preparation of Coating Composition (Ink) As described above, the coating composition contains metal fine particles that are the growth nuclei of plating and a binder (ink base) having adhesiveness to the substrate. Prepare.

  As described above, the metal fine particles are mainly composed of a single metal selected from Pt, Pd, Ni, Cu, Ti, V, Mn, Fe, Co, Ag, and Au, or an alloy composed of two or more metals. Metal fine particles having a particle diameter of 1 nm to 1 mm are preferably used.

  The content of the metal fine particles is preferably about 100 to 100,000 ppm by mass ratio with respect to the binder, and more preferably 1000 to 4000 ppm.

  As described above, as the binder, a single binder or a mixed binder selected from acrylic, urethane, hexane, styrene, benzene, ethers, and an acetic acid organic compound is preferably used from the viewpoint of adhesion to the substrate.

  As described above, a dispersant may be added to the coating composition in order to further improve the dispersibility of the metal fine particles, and a solvent is added as a viscosity modifier to facilitate application to the substrate. May be.

  Examples of the dispersant include a polycarboxylic acid-based dispersant, an isocyanate-modified polyol-based dispersant, a polyvinyl alcohol-based dispersant, an aromatic sulfonic acid-based dispersant, polyethylene glycol, polyethylene glycol phosphate, polyvinyl pyrrolidone, and polyethylene glycol alkyl. Ether, polyethylene glycol polypropylene glycol copolymer and the like can be used.

  Examples of the solvent include methanol, ethanol, 1-propanol, isopropanol, 1-butanol, isobutanol (isobutyl alcohol), ethylene glycol, cyclohexanol and other alcohols; acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, Ketones such as cyclohexanone; esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate and cellosolve; ethers such as methyl cellosolve, ethyl cellosolve, tetrahydrofuran and 1,4-dioxane; toluene, xylene, cyclohexane and methyl Hydrocarbons such as cyclohexane and ethylcyclohexane; N-methylpyrrolidone (NMP), N, N-dimethylacetamide (DMAC), N, N-dimethylform Nitrogen-containing compounds such as imide (DMF), 1,3-dimethyl-2-imidazolidinone (DMI), N, N′-dimethylimidazolidinone; sulfur-containing compounds such as dimethyl sulfoxide (DMSO) Can be used.

  In addition, additives such as dispersion stabilizers, thickeners, antioxidants, ultraviolet absorbers, hindered amine light stabilizers, pigments, hydrolysis inhibitors and the like may be appropriately added to the coating composition.

(2) Application of Coating Composition (Ink) Next, as shown in FIG. 1B, the coating composition is applied to the surface of the substrate 10 (resin film 12) to form a coating film 13.

  The coating can be performed using a bar coater as shown in FIG. 1 (b), but other methods such as drip coating, gravure printing, ink jet printing, dipping, spraying, spin coater, roll coater, reverse coater. A method using a doctor coater, screen printing, or the like may be used.

  The coating thickness is appropriately set in consideration of the thickness of the coating film to be baked. Usually, about 1 to 30 μm (forming a coating film having a thickness of about 0.1 to 3 μm) is preferable, and 3 to 20 μm (thickness). It is more preferable that the coating film has a thickness of 15 to 2 μm.

(3) Baking treatment The coating film 13 applied to the surface of the substrate 10 is then dried by hot air in an electric furnace or the like and cured as shown in FIG. Thereby, the coating film 13 in which the metal fine particles are encapsulated in the binder and the resin film 12 are sufficiently adhered.

  In addition, although the temperature, time, etc. in a baking process are suitably set according to a composition, application | coating thickness, etc. of a coating composition, 100-140 degreeC is preferable and 100-120 degreeC is more preferable. The baking time is preferably about 30 minutes.

3. Next, as shown in the upper part of FIG. 1D, vacuum plasma is applied to the coating film 13 from the upper surface of the coating film 13. As the gas to be converted into plasma, the aforementioned O ₂ , O ₃ , N ₂ , H ₂ , Ar, He, H ₂ O, CF ₄ , CHF ₃ , CO, CO ₂ , or a mixed gas thereof can be used. .

  Such gas is turned into plasma and vacuum plasma treatment is performed at a frequency of 1 to 1000 MHz in an atmosphere of 1 to 1000 Pa. Thereby, as shown in the middle of FIG. 1D, organic components (organic components such as a dispersant and a binder) in the vicinity of the surface of the coating film 13 covering the periphery of the metal fine particles 14 are decomposed and removed, As shown in the lower part of FIG. 1D, the metal fine particles 14 are exposed on the surface of the coating film 13.

  Further, by applying vacuum plasma, the exposed surface of the metal fine particles 14 is reduced, and sufficient catalytic activity is given to the surface of the metal fine particles 14.

  Here, the vacuum plasma will be described with reference to FIG. FIG. 2 is a diagram schematically showing an example of the configuration of the plasma processing apparatus used in the present embodiment. In FIG. 2, 1 is a vacuum chamber, 2 is a processing gas inlet, 3 is an upper electrode (ground electrode), 4 is a lower electrode (feed electrode), 5 is a matching unit, 6 is a high-frequency oscillator, and 7 is a vacuum valve. , 8 is a vacuum pump, and 10 is a substrate on which a coating film 13 (see FIG. 1) is formed.

  By applying a predetermined voltage between the upper electrode 3 and the lower electrode 4 facing each other, the processing gas is turned into plasma (ionization, light emission) between the upper electrode 3 and the lower electrode 4 facing each other, and the lower electrode The substrate 10 set on the substrate 4 is irradiated with plasma. The process gas is always introduced into the vacuum chamber 1 from the process gas inlet 2, but since the exhaust capacity of the vacuum pump 8 exceeds the amount of process gas introduced, the vacuum chamber 1 is kept in a reduced pressure state. Be drunk.

Further, this plasma treatment does not have to be performed under fixed conditions from the beginning to the end, and may be performed by continuous step treatment by appropriately changing the plasma recipe such as the type of gas and plasma conditions. For example, first, vacuum plasma processing using O ₂ as a processing gas is performed to decompose and remove organic components of the coating film 13 to expose the metal fine particles 14, and then (Ar + H ₂ ) is used as the processing gas. The exposed surface of the metal fine particles 14 is reduced and activated by performing vacuum plasma treatment. By doing in this way, since the surface of the metal fine particle 14 can be activated more fully, a plating characteristic can be improved more.

  The treatment time is preferably about 0.5 to 10 minutes, and more preferably 1 to 3 minutes.

4). Electroless Plating Next, as shown in FIG. 1E, an electroless plated film 15 is formed on the surface of the coating film 13 where the metal fine particles 14 are exposed by electroless plating. Since the surface of the metal fine particles 14 is activated by the plasma treatment, the electroless plating film 15 is formed in close contact with the surface of the coating film 13 using the metal fine particles 14 as growth nuclei.

  The plating conditions may be the same as the conventional plating conditions. For example, in the case of electroless copper plating, the temperature of the plating bath is 25 to 45 ° C., preferably 30 to 35 ° C., and is treated for about 10 to 15 minutes. By doing so, a film thickness of about 0.3 to 0.4 μm can be obtained.

5. Electrolytic plating Finally, as shown in FIG. 1 (f), an electrolytic plating film 16 is formed on the electroless plating film 15 to a predetermined thickness, and the production of the plated substrate is completed. The plating conditions may be the same as the conventional plating conditions.

  Hereinafter, based on an Example, this invention is demonstrated more concretely.

(Experiment 1)
In Experiment 1, 16 types of experiments with different substrate configurations, coating composition compositions, presence / absence of vacuum plasma, and plasma processing conditions were performed to determine plating characteristics in electroless copper plating and adhesion between the electroless copper plating film and the substrate. Sex was evaluated.

1. Preparation of test body (1) Preparation of substrate A substrate was prepared based on the above-described embodiment. Specifically, a glass epoxy (glass epoxy) base material (size: 20 × 90 mm, thickness: 1 mm), which is a general plated substrate material, is used as a base material (base), and a commercially available low-priced material having a thickness of about 30 μm. A substrate on which a dielectric film (film for a high-frequency substrate) was laminated was used. In addition, the film A and the film B shown in Tables 1 and 2 are low dielectric constant films made of the same material only with different colors.

(2) Preparation of coating composition (ink) Commercially available Pd ink was used as the coating composition. In this ink, the ink base (binder) shown in Tables 1 and 2 contains 250 ppm of Pd particles having a particle diameter of 5 to 10 nm.

(3) Application The prepared coating composition for electroless plating was applied onto the substrate by drip coating to form a coating film having a thickness of about 30 μm.

(4) Baking process (fixation)
Next, the coating was fixed by heating at 100 ° C. for 30 minutes using an electric furnace. The thickness of the coating film after baking was 20 μm.

(5) Vacuum plasma treatment Next, vacuum plasma treatment was performed under the conditions shown in Tables 1 and 2 (atmospheric pressure: 20 Pa, frequency 13.56 MHz). In Tables 1 and 2, a portion written in two steps indicates that a two-stage vacuum plasma treatment was performed.

(6) Electroless plating Next, electroless plating was performed at a bath temperature of 33 to 37 ° C. for 15 minutes using an electroless plating solution (trade name Sulcup PSY) manufactured by Uemura Kogyo Co., Ltd.

2. Evaluation of plating (1) Evaluation method Plating characteristics The appearance of the electroless copper plating film on the substrate was evaluated by visual observation.

B. Adhesiveness The adhesiveness between the electroless copper plating film and the substrate was evaluated by measuring the peel strength by the tape peeling method.

(2) Evaluation results Tables 1 and 2 show the evaluation results.

  From Tables 1 and 2, regardless of the material of the substrate surface and the type of ink base, when the plasma treatment is not performed (Experimental Examples 1, 5, 9, and 13), the plating characteristics and adhesion are not good. Was confirmed.

  And even if it performed vacuum plasma processing, when processing time was 1 minute (Experimental example 2, 6, 10, 14), it has confirmed that a plating characteristic and adhesiveness were not good irrespective of gas kind.

  In contrast, when the treatment time was 2 minutes or longer (Experimental Examples 3, 4, 7, 8, 11, 12, 15, 16), it was confirmed that both the plating characteristics and the adhesion were good. .

  From this result, it can be seen that the characteristics of electroless copper plating are improved with respect to all ink bases by increasing the vacuum plasma treatment time, and that vacuum plasma treatment is effective as a technique for improving the plating characteristics. It could be confirmed.

(Experiment 2)
In Experiment 2, eight types of experiments with different substrate configurations and plasma processing conditions were performed, and the plating characteristics and adhesion were similarly evaluated.
-Substrate surface: Film A, Film B
-Plasma treatment: conditions shown in Table 3-Other conditions: shown in Table 3.

  Note that “cm / min” shown in the upper part of the processing time in Table 3 indicates that the scan speed was scanned the number of times shown in the lower part. Note that the scan time per time is 2 minutes.

2. Evaluation of plating Evaluation was performed in the same manner as in Experiment 1.

3. Evaluation results Table 3 shows the evaluation results.

  From Table 3, in the case of atmospheric plasma treatment (Experimental Examples 19 to 24), it was confirmed that good plating characteristics could not be obtained even if the number of scans (number of treatments) was increased. On the other hand, in the case of the vacuum plasma treatment (Experimental Examples 17 and 18), glossy copper was deposited and the plating characteristics were good.

In Experimental Examples 17 and 18, partial peeling was observed in the plating. From the results of Experimental Example 16 and Experimental Example 18 in which only the processing gas is different, it is presumed that O ₂ + CF ₄ is inferior in surface activation effect compared to O ₂ .

  From this result, it was confirmed that the atmospheric plasma treatment did not exert an effect for improving the plating characteristics and adhesion. In addition, even in the vacuum plasma treatment, it was confirmed that if the gas was not properly selected, the adhesion could not be sufficiently high even though the plating characteristics could be ensured.

(Experiment 3)
In Experiment 3, seven types of inks having different Pd particle contents and baking conditions were performed, and the plating characteristics and adhesion were similarly evaluated.

1. Preparation of specimen / ink: Pd particle content 1000 ppm, 2000 ppm, 4000 ppm
Bake temperature: 120 ° C, 140 ° C, 160 ° C, 180 ° C, 200 ° C
Other conditions: Table 4 shows.

2. Evaluation of plating Evaluation was performed in the same manner as in Experiment 1.

3. Evaluation results Table 4 shows the evaluation results.

  From Table 4, it can be seen that ink having a Pd content of 1000 ppm provides good plating characteristics and adhesion when the baking temperature is 120 ° C. (Experimental Example 25), but these characteristics decrease as the baking temperature increases. Was confirmed. Further, it was confirmed that the plating characteristics were not improved even when the Pd content was increased at a baking temperature of 140 ° C.

  From this result, it was confirmed that even if the Pd content was increased, the plating characteristics and adhesion were not improved.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to said embodiment. Various modifications can be made to the above-described embodiment within the same and equivalent scope as the present invention.

1 Vacuum chamber 2 Process gas inlet 3 Upper electrode (ground electrode)
4 Lower electrode (feeding electrode)
5 Matching Unit 6 High Frequency Oscillator 7 Vacuum Valve 8 Vacuum Pump 10 Substrate 11 Base Material 12 Resin Film 13 Coating 14 Metal Fine Particle 15 Electroless Plating Coating 16 Electrolytic Plating Coating

Claims (8)

A plating method for forming a conductor film on the surface of an electrically insulating substrate,
On the surface of the substrate, a coating composition is formed by applying a coating composition containing fine metal particles serving as a growth nucleus of plating and a binder having adhesiveness to the substrate, and forming a coating film,
A plasma treatment step of decomposing and removing organic components near the surface of the coating film by vacuum plasma to expose the metal fine particles on the surface of the coating film and activating the exposed metal fine particles;
Electroless plating is performed on the surface of the plasma-treated coating film to form an electroless plating film; and
A plating method comprising: an electroplating step of performing electroplating on the surface of the electroless plating film to grow the electroplating film to a predetermined thickness. The gas to be plasmified in the plasma treatment step is one or more selected from O ₂ , O ₃ , N ₂ , H ₂ , Ar, He, H ₂ O, CF ₄ , CHF ₃ , CO, and CO _2. The plating method according to claim 1, wherein the plating method is provided.   The plating method according to claim 1, wherein the plasma treatment is a vacuum plasma treatment performed under conditions of a pressure of 1 to 1000 Pa and a frequency of 1 to 1000 MHz.   Prior to the coating film forming step, the substrate is provided with a plasma processing step of performing atmospheric plasma processing on the substrate under conditions of a pressure of 0.1 ± 0.01 MPa and a frequency of 1 to 100 kHz. 4. The plating method according to any one of 3 above.   The substrate is epoxy resin, polyimide, polypropylene, polyethylene terephthalate, polyethylene, polystyrene, acrylic resin, polyvinyl chloride, polyvinyl acetate, fluororesin, ABS resin, AS resin, phenol resin, melamine resin, polyester, polyurethane, urea resin The plating method according to any one of claims 1 to 4, wherein the main component is one or more selected from alkyd resins. The metal fine particles are
The main component is a single metal selected from Pt, Pd, Ni, Cu, Ti, V, Mn, Fe, Co, Ag, Au, or an alloy composed of two or more metals.
The plating method according to any one of claims 1 to 5, wherein the fine particle is a metal fine particle having a particle diameter of 1 nm to 1 mm.   The binder according to any one of claims 1 to 6, wherein the binder is mainly composed of one or more selected from acrylic, urethane, hexane, styrene, benzene, ethers, and acetic acid organic compounds. The plating method as described.   A plated wiring formed by processing a conductor film formed on a smooth electrical insulating substrate using the plating method according to claim 1.

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