RESIN ARTICLE HAVING PLATING LAYER AND MANUFACTURING METHOD THEREOF

There is provided with a method for manufacturing a resin article having a plating layer, obtained by forming a plating layer on a portion of the surface of a resin article. The surface of the resin article is treated with a mask material solution. A portion of the surface of the resin article is irradiated selectively with ultraviolet rays such that it is possible to apply an electroless plating catalyst to the portion of the surface of the resin article. An electroless plating catalyst is applied to the portion of the surface of the resin article irradiated with ultraviolet rays. A plating layer is formed on the portion of the surface of the resin article irradiated with ultraviolet rays, using electroless plating.

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Description
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a resin article having a plating layer and a manufacturing method thereof.

2. Description of the Related Art

A resin article provided with a plating layer having a predetermined pattern is useful as, for example, a wiring board, a conductive film, or the like. A method in which electroless plating is used has been known as a method for manufacturing such a resin article having a plating layer.

For example, Japanese Patent Laid-Open No. 2008-094923 discloses a method for manufacturing a wiring board using surface modification by means of ultraviolet rays. Specifically, first, the entire surface of a cyclo-olefin polymer base material is irradiated with ultraviolet rays emitted from an ultraviolet lamp, and thus the surface of the base material is modified. An electroless plating layer is likely to be deposited on the modified region. Thereafter, an alkali degreasing treatment is performed on the base material. It is thought that this treatment is performed in order to improve adhesion with the catalyst ions or a binder material that binds together catalyst ions and the base material, the plating layer, and the like by cleaning the surface, and by increasing hydrophilicity and forming fine surface roughness. Furthermore, a conditioning treatment is performed on the base material, and with this treatment, a binder material for binding together catalyst ions and the base material is applied to the base material. The catalyst ions are adsorbed on the binder material and reduced to deposit a catalyst metal, whereafter electroless plating is performed, and thereby a metal plating layer is formed on the entire surface of the modified cyclo-olefin polymer material. Finally, photolithography and etching are performed, whereby the metal plating layer is patterned so as to have a desired pattern.

Japanese Patent Laid-Open No. 2009-007613 discloses a method for forming a metal thin film pattern on the surface of a polyimide resin base material. Specifically, a resist pattern is formed on the surface of the polyimide resin base material, and by performing alkali modification, addition of fine metal particles, and electroless plating on a portion exposed through an opening portion of the resist pattern, a metal thin film is formed on the opening portion of the resist pattern. The polyimide resin base material has particularly excellent heat resistance compared to other resin base materials, and in one example, has a Tg of 200° C. or more. Also, the polyimide resin base material has high mechanical strength, high versatility, and can also be processed into a film, for example. For these reasons, most flexible substrates are made of polyimide resin.

SUMMARY OF THE INVENTION

According to an embodiment of the present invention, a method for manufacturing a resin article having a plating layer, obtained by forming a plating layer on a portion of a surface of a resin article, includes: treating the surface of the resin article with a mask material solution; irradiating a portion of the surface of the resin article selectively with ultraviolet rays such that it is possible to apply an electroless plating catalyst to the portion of the surface of the resin article; applying the electroless plating catalyst to the portion of the surface of the resin article irradiated with ultraviolet rays; and forming a plating layer on the portion of the surface of the resin article irradiated with ultraviolet rays, using electroless plating.

According to another embodiment of the present invention, a resin article having a plating layer is manufactured using a method including: treating a surface of a resin article with a mask material solution; irradiating a portion of the surface of the resin article selectively with ultraviolet rays such that it is possible to apply an electroless plating catalyst to the portion of the surface of the resin article; applying the electroless plating catalyst to the portion of the surface of the resin article irradiated with ultraviolet rays; and forming a plating layer on the portion of the surface of the resin article irradiated with ultraviolet rays, using electroless plating.

Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a method for manufacturing a resin article having a plating layer according to an embodiment.

FIG. 2 is a flowchart for a method for manufacturing a resin article having a plating layer according to an embodiment.

FIG. 3 is a diagram showing a mask used in an example and a comparative example.

FIG. 4 is a diagram illustrating a method for manufacturing a resin article having a plating layer according to an example and a comparative example.

 DESCRIPTION OF THE EMBODIMENTS

Photolithography and etching are needed in order to form a plating layer having a desired pattern using the method disclosed in Japanese Patent Laid-Open No. 2008-094923. Also, a resist pattern needs to be formed using photolithography in the method disclosed in Japanese Patent Laid-Open No. 2009-007613 as well. For this reason, the methods disclosed in Japanese Patent Laid-Open No. 2008-094923 and Japanese Patent Laid-Open No. 2009-007613 are problematic in terms of cost, and in that the environmental burden is high since a large amount of waste liquid is produced.

According to an embodiment of the present invention, a plating layer having a desired pattern can be formed on a resin article at low cost.

The inventor knew of a technique in which the technique disclosed in Japanese Patent Laid-Open No. 2008-094923 is adapted such that instead of irradiating the entire surface of a resin article with ultraviolet rays, a portion of the surface of the resin article is selectively modified by being selectively irradiated with ultraviolet rays in accordance with a desired pattern. With this technique, a plating layer is selectively deposited using electroless plating on the portion irradiated with ultraviolet rays. That is, a plating layer having a desired pattern can be obtained without using a photolithography step or an etching step.

However, the inventor encountered a problem in that even if such a technique is used, the shape of the resulting plating layer is not stable in some cases. For example, the inventor found that depending on conditions such as the type of the resin article used, the plating layer is sometimes deposited also on a portion that was not irradiated with ultraviolet rays. For example, in the case of using a polyimide resin base material, when electroless plating was performed after performing selective irradiation with ultraviolet rays, the plating layer was deposited also on a portion that was not irradiated with ultraviolet rays, and therefore a plating layer having a desired pattern was not obtained.

The inventor speculates that the reason for this is as follows. First, an example of the molecular structure of polyimide will be shown below.

Imide rings are opened by performing an alkali treatment on polyimide, and thereby a carboxyl group COOH, which is a chemical adsorption group, is produced as shown below.

According to the method disclosed in Japanese Patent Laid-Open No. 2008-094923, the alkali degreasing treatment is performed, and conditioning treatment is performed using a binder solution (conditioner) that is usually alkaline. In such a case, it is thought that the imide rings of polyimide are opened by the alkali degreasing treatment and the conditioning treatment, whereby a chemical adsorption group is produced also on a portion that was not irradiated with ultraviolet rays. Also, since carbonyl groups (═O), which are chemical adsorption groups, are present in the molecular structure of the polyimide, wettability is high. For this reason, it is thought that the conditioner tends to be adsorbed on the polyimide even if the imide rings are not opened.

As a result of examination, the inventor found that the mask material on the region irradiated with ultraviolet rays can be deactivated by treating the surface of the resin article with a mask material solution and thereafter performing selective irradiation with ultraviolet rays. When electroless plating was performed thereafter, the plating layer was not deposited on the portion that was not irradiated with ultraviolet rays.

Using this new method made it possible to perform selective plating with good reproducibility even in the case of using resin modified by an alkali solution, or resin with high wettability. That is, a plating layer having a desired pattern could be formed on a resin article at low cost without using a photolithography step and an etching step.

Hereinafter, an embodiment according to which the present invention can be applied will be described with reference to the drawings. However, the scope of the present invention is not limited to the following embodiment.

A method for manufacturing a resin article 100 having a plating layer according to an embodiment of the present invention includes a modifying step, a first applying step, an ultraviolet ray irradiation step, a second applying step, and a plating step. Hereinafter, each of these steps will be described with reference to FIGS. 1 and 2.

Modifying Step

In the modifying step (step S210), treatment for modifying at least a portion of a surface 120 of a resin article 110 is performed on the resin article 110 that needs to be modified in order to cause a plating layer to be deposited thereon in the plating step. The modifying step makes it easier to deposit the plating layer on the resin article 110 and makes it easier to attach the mask material in the first applying step. In an embodiment, the modifying step can be omitted for a resin article on which the plating layer can be deposited in the plating step even without performing modification, and to which the mask material can be applied in the masking step. In 1a in FIG. 1, the resin article 110 and the resin article surface 120 are shown. In 1b in FIG. 1, a modified resin article surface 130 of the resin article 110 resulting from the modifying step is shown.

There is no particular limitation on the material of the resin article 110. In particular, the method for manufacturing of the present embodiment can be used for the resin article 110 having a polyimide resin or a polyamide resin on its surface. Among these, the polyimide resin has excellent heat resistance and strength, and therefore soldering (including reflow) can be performed on a wiring board obtained by forming a plating layer pattern on a polyimide resin substrate.

The resin article 110, which includes a material that is modified by an alkali solution, can also be used in the present embodiment. In an embodiment, a chemical adsorption group is produced on the surface of the resin article 110 due to hydrolysis caused by the alkali treatment. Examples of the chemical adsorption group include a hydroxyl group, a carbonyl group, a carboxyl group, and the like. Also, in an embodiment, the surface of the resin article 110 includes at least one of an imide bond, an amide bond, and an ester bond.

In the present embodiment, a resin article 110 constituted by a material having high wettability can also be used. In an embodiment, the surface of the resin article 110 includes a material having at least one of a hydroxyl group, a carbonyl group, and a carboxyl group. A resin having this kind of functional group has high wettability.

There is no particular limitation on the shape of the resin article 110, and it can be in the form of a plate, film, or the like, for example. Also, the resin article 110 may be constituted by multiple resin materials, may have a structure in which multiple resin materials are layered, or may be constituted by a compound material including a coating structure obtained by coating the surface of another material with a resin material.

Examples of modification methods include, but are not limited to, irradiation with ultraviolet rays, acid treatment using chromic acid or the like, and alkali treatment using sodium hydroxide or the like. Also, it is possible to use two or more modification methods in combination in the modification step.

In one embodiment, the resin article 110 is modified using an alkali solution. That is, the resin article 110 has a property in which bonds between molecules on the surface thereof are cut by the alkali treatment. Examples of resin materials that are easily modified by an alkali treatment include polyimide resin, polyamide resin, polycarbonate resin, acrylic resin, and polyester resin.

For example, if polyimide resin is used as the resin article 110, when the alkali treatment is performed on the resin article 110, imide rings are opened, and carboxyl groups or carboxyl ions are produced on the surface 120 of the resin article 110. Since the carboxyl groups or carboxyl ions have a high affinity with the later-described mask material, the mask material is more easily adsorbed on the surface 120 in the first applying step (step S220). For this reason, it is thought that after the mask material at a region 150 irradiated with ultraviolet rays is deactivated, electroless plating is more likely to be deposited on the surface of the resin article 110 modified by the alkali treatment.

The alkali treatment may be performed on the entire resin surface 120, or it may be selectively performed on a portion of the resin surface that includes the region 150 irradiated with ultraviolet rays, which will be described later. In this case, the conditions for the alkali treatment may be selected as appropriate, such that the plating layer is deposited on the region 150 that is irradiated with ultraviolet rays and at which the mask material is deactivated, and the plating layer is not deposited on the region that is not irradiated with ultraviolet rays and at which the mask material remains.

In an embodiment, the alkali treatment is performed by immersing the resin article 110 in an alkali treatment solution. For example, it is possible to use an aqueous solution of an alkali metal hydroxide, an alkali earth metal hydroxide, or the like as the alkali treatment solution. Specific examples of the alkali treatment solution include an aqueous solution of sodium hydroxide, an aqueous solution of potassium hydroxide, and the like. After the alkali treatment, the resin article 110 may be cleaned by washing with water, or the like.

First Applying Step

In the first applying step (S220), the mask material is applied to the surface of the resin article 110 as shown in 1c in FIG. 1. In 1c in FIG. 1, a region 140 of the resin article 110 to which the mask material has been applied, resulting from the first applying step, is shown. In the case of using a resin article 110 having a property such that the mask material attaches easily thereto, the above-described modifying step may be omitted. In an embodiment, each oxygen atom existing on the modified surface is high in electro-negativity and strongly attracts electrons in the molecule, and therefore has a negative charge. In another embodiment, imide bonds (—CONCO—) in primary chains of the polyimide resin undergo imide ring opening due to the alkali treatment in the modifying step, and thus have a negative charge. The mask material may be thus applied to the surface of the resin having a negative charge or an adsorption group.

The mask material may include an ion polymer as a component. Ion polymers include cation polymers, anion polymers, and non-ion polymers. Specifically, a mask material that easily attaches to the surface of the resin article 110 can be used. For example, in an embodiment in which a resin article 110 having a surface with a negative charge is used, a cation polymer is used as the mask material. Thus, a mask material having a charge opposite to that of the surface of the resin article 110 can be used as a mask material that easily attaches to the surface of the resin article 110. In an embodiment, the mask material is in the form of a solution. Application of the mask material can be performed by treating the surface of the resin article 110 with the mask material solution, and for example, it can be performed by bringing the mask material solution into contact with the surface of the resin article. In an embodiment, the first applying step may be performed by immersing the resin article 110 in the mask material solution. In another embodiment, the first applying step may be performed by spraying the mask material solution onto the resin article 110 or coating the resin article 110 with the mask material solution.

It is thought that the mask material is deactivated due to the mask material being selectively irradiated with ultraviolet rays in a later step. Then, in an even later step, a catalyst is adsorbed on the surface of the resin article 110, and thus an electroless plating layer is deposited at that region. As long as a desired property is obtained, the mask material may remain on the resin article having a plating layer after all of the steps are complete, and there is no need to include a step of removing the mask material.

Ultraviolet Ray Irradiation Step

In an ultraviolet ray irradiation step (step S230), the resin article 110 to which the mask material has been applied is selectively irradiated with ultraviolet rays, as shown in 1d in FIG. 1. In 1d in FIG. 1, the region 150 that was selectively irradiated with ultraviolet rays, and the region 140 that was not irradiated with ultraviolet rays and to which a mask material was applied are shown. In the ultraviolet ray irradiation step, a region on at least a portion of the surface of the resin article 110 to which the mask material has been applied is irradiated with ultraviolet rays such that an electroless plating catalyst can be applied to the portion of the surface of the resin article 110 to which the mask material has been applied. It is thought that by performing irradiation with ultraviolet rays, the mask material applied to the surface of the resin article 110 is deactivated.

In an embodiment, the resin article 110 is irradiated with ultraviolet rays in an atmosphere including at least one of oxygen and ozone. As a specific example, the resin article 110 can be irradiated with ultraviolet rays in air. In another embodiment, in order to further promote the deactivation of the mask material, irradiation is performed in an atmosphere including ozone.

For example, upon performing irradiation with ultraviolet rays having a specific wavelength or less that can decompose oxygen in an atmosphere including oxygen, the oxygen in the atmosphere is decomposed to produce ozone. Furthermore, active oxygen is produced in the process of decomposing ozone.

The energy of a photon having a specific wavelength can be represented by the following equation.


E=Nhc/λ(KJ·mol−1)

N=6.022×1023 mol−1 (Avogadro's number)

h=6.626×10−37 KJ·s (Planck constant)

c=2.988×108 m·s−1 (speed of light)

λ=light wavelength (nm)

Here, the binding energy of an oxygen molecule is 490.4 KJ·mol−1. The light wavelength is approximately 243 nm when converted from the binding energy based on the equation for the energy of photons. This indicates that the oxygen molecules in the atmosphere absorb ultraviolet rays having a wavelength of 243 nm or less and are decomposed. As a result, ozone O3 is produced. Furthermore, during decomposition of ozone, active oxygen is produced. At this time, if ultraviolet rays having a wavelength of 310 nm or less are present, ozone is efficiently decomposed to produce active oxygen. Furthermore, ultraviolet rays having a wavelength of 254 nm decompose ozone most efficiently.


O2+hν (243 nm or less)→O(3P)+O(3P)


O2+O(3P)→O3 (ozone)


O3+hν (310 nm or less)→O2+O(1D) (active oxygen)

O(3P): oxygen atom in ground state

O(1D): oxygen atom in excited state (active oxygen)

There is no particular limitation on the method for irradiation with ultraviolet rays, and for example, it is possible to use an ultraviolet lamp, an ultraviolet LED, an ultraviolet laser, or the like. In an embodiment, the region 150 to be irradiated is irradiated with ultraviolet rays emitted from an ultraviolet lamp or the like through a quartz chromium mask in which a desired pattern is formed. In another embodiment, the region 150 to be irradiated with ultraviolet rays is scanned with ultraviolet rays using ultraviolet rays from an ultraviolet laser or the like.

In the present embodiment, the portion of the surface of the resin article 110 on which the electroless plating is to be deposited is selectively irradiated with ultraviolet rays. It is thought that the mask material applied to the surface of the resin article 110 is deactivated at the portion irradiated with ultraviolet rays, and as a result, an electroless plating catalyst can be applied thereto. For example, by performing irradiation with ultraviolet rays via a mask having an ultraviolet ray transmission portion with a shape corresponding to the plating pattern to be deposited, the region 150 to be irradiated with ultraviolet rays can be selectively irradiated with ultraviolet rays. An example of the mask is shown in FIG. 3. The photomask 300 shown in FIG. 3 includes a substrate 310 that transmits ultraviolet rays, and a metal thin film 320 that is provided on the substrate 310 and does not transmit ultraviolet rays. The metal thin film 320 is patterned so as to have an opening having a shape that corresponds to the region 150 to be irradiated with ultraviolet rays.

There is no particular limitation on the wavelength of the ultraviolet rays, and a wavelength that promotes deactivation of the mask material applied to the resin surface is selected. In an embodiment, the wavelength of the ultraviolet rays is 243 nm or less. Due to the wavelength being 243 nm or less, the deactivation of the mask material on the surface of the resin article 110 is further promoted. Ultraviolet rays with a wavelength of 243 nm or less can decompose oxygen in the atmosphere, and can produce ozone and active oxygen.

There is no particular limitation on the irradiation amount of ultraviolet rays, and the irradiation amount can be selected as appropriate such that the mask material of the region 150 irradiated with ultraviolet rays is deactivated and the plating is selectively deposited on the region 150 irradiated with ultraviolet rays. In general, it is thought that the larger the irradiation amount of ultraviolet rays is, that is, the higher the intensity of the ultraviolet rays is or the longer the irradiation time is, the more the deactivation of the mask material at the region 150 irradiated with ultraviolet rays advances and the easier it is for the plating to be deposited. However, the inventor confirmed, by means of an experiment, that the deposition of the plating deteriorates in some cases if the irradiation amount of ultraviolet rays exceeds an appropriate amount. The inventor speculates that the reason for this is that the modified layer on the surface of the resin article 110 falls off when the deactivation of the mask material advances and the ultraviolet rays reach the surface of the resin article 110.

In an embodiment, the cumulative irradiation amount of ultraviolet rays at the primary wavelength can be 600 mJ/cm2 or more, or 800 mJ/cm2 or more. In an embodiment, the cumulative irradiation amount at the primary wavelength is 1200 mJ/cm2 or less. In the present specification, unless otherwise stated, the irradiation amount and irradiation intensity of ultraviolet rays indicate values at the primary wavelength. In the present specification, the primary wavelength indicates the wavelength with the highest intensity in a range of 243 nm and less. Specifically, in the case of using a low-voltage mercury lamp, the primary wavelength is 185 nm.

The conditions for deactivating the mask material may change depending on the type of the resin article 110, the existence of modification of the resin surface and the state thereof, the level of contamination of the surface of the resin article 110, the type of the mask material, the thickness of the mask material, the type of the plating solution, the concentration, temperature, pH, and deterioration over time of the plating solution, variation in the output of the ultraviolet lamp, or the like. In this case, it is sufficient that the irradiation amount of ultraviolet rays is determined as appropriate with reference to the foregoing values.

Second Applying Step

In the second applying step (step S240), an electroless plating catalyst is applied to the surface of the resin article 110 irradiated with ultraviolet rays. Specifically, as shown in 1e in FIG. 1, an electroless plating catalyst is applied to the region 150 irradiated with ultraviolet rays.

The electroless plating catalyst can be applied in accordance with a conventionally-known method. For example, the electroless plating catalyst can be applied by using the following two steps.

The catalyst is applied by bringing a catalyst ion solution into contact with the surface of the resin article 110. In an embodiment, the catalyst may be applied by immersing the resin article 110 in the catalyst ion solution. In another embodiment, the catalyst may be applied by spraying the catalyst ion solution onto the resin article 110 or coating the resin article 110 with the catalyst ion solution.

The catalyst ions are reduced by immersing the resin article 110 in a solution containing a reducing agent. Thus, the catalyst is deposited. Examples of the reducing agent include hydrogen gas, dimethylamine borane, sodium borohydride, and the like.

An electroless plating catalyst is used which easily attaches to locations at which the mask material on the surface of the resin article 110 is deactivated, and which is not likely to attach to the mask material on the resin article 110. For example, the electroless plating catalyst can be applied by using an electroless plating catalyst having a charge opposite that of the surface of the resin article 110 after the mask material has been deactivated. In this case, the electroless plating catalyst selectively attaches to the region 150 irradiated with ultraviolet rays. On the other hand, the electroless plating catalyst does not attach to the region 140 that was not irradiated with ultraviolet rays and to which the mask material was applied. Specific examples of the electroless plating catalyst include a cation catalyst such as an activator solution (product name ELFSEED ES-300, available from JCU Corporation) containing a palladium complex (e.g., a palladium (II)-basic amino acid complex) having a positive charge in at least a portion thereof. A palladium-basic amino acid complex disclosed in WO 2007/066460 can be used as another example of a palladium-basic amino acid complex. It is possible to perform the second applying step (step S240) by using an activator solution for electroless plating including this kind of electroless plating catalyst. This kind of palladium complex having a positive charge in at least a portion thereof is likely to interact with the chemical adsorption group produced on the surface of the resin article 110 after the mask material is deactivated.

Specific examples of the reducing agent include a cation activating agent such as an accelerator solution (product name: ELFSEED ES-400, available from JCU Corporation).

Plating Step

In the plating step (step S250), the resin article 110 to which the electroless plating catalyst has been applied is immersed in the electroless plating solution. In if in FIG. 1, a resin article 100 having a plating layer, in which a plating layer 170 has been deposited on the region 150 irradiated with ultraviolet rays, is shown.

There is no limitation on the specific method for electroless plating. Examples of electroless plating that can be used include electroless plating using a formalin-based electroless plating bath, and electroless plating using hypophosphorous acid as the reducing agent, which has a slow depositing speed but is easy to handle. Also, the plating layer 170 may be formed using a high-speed electroless plating method in order to form a thicker plating layer. Further specific examples of electroless plating include electroless copper plating, electroless copper nickel plating, and zinc oxide plating.

Electroless plating according to such a method can be performed using, for example, an electroless Cu—Ni plating solution (product name: AISL-520, available from JCU Corporation). In the case of using hypophosphorous acid as the reducing agent, copper nickel plating in which nickel is used is performed in order to give the plating layer self-catalyzing properties.

The plating layer 170 formed using electroless plating in this way is often thin, and therefore the thickness of the plating layer 170 may be increased by further performing electrolytic plating. In 1g in FIG. 1, the plating layer 180 whose thickness has been increased by further performing electrolytic plating is shown. Examples of the material of the metallic layer provided using electrolytic plating include, but are not limited to, copper, nickel, copper-nickel alloy, zinc oxide, zinc, silver, cadmium, iron, cobalt, chromium, nickel-chromium alloy, tin, tin-lead alloy, tin-silver alloy, tin-bismuth alloy, tin-copper alloy, gold, platinum, rhodium, palladium, and palladium-nickel alloy. Also, silver or the like may be deposited on the plating layer 170 by displacement plating.

According to the method of the present embodiment, the plating layer 170 is deposited on the region 150 irradiated with ultraviolet rays by performing electroless plating. On the other hand, even if electroless plating is performed, the plating layer 170 is not deposited on the region that was not irradiated with ultraviolet rays. For example, the plating layer is not deposited on the region adjacent to the region 150 irradiated with ultraviolet rays. Thus, according to the method of the present embodiment, the plating layer 170 can be selectively deposited with good reproducibility on the region 150 irradiated with ultraviolet rays.

EXAMPLES Example 1

A polyimide plate (product name: Kapton EN200, thickness: 50 μm, available from DuPont-Toray Co., Ltd.) was used as a resin article 410. Table 1 shows the steps performed in Example 1.

TABLE 1 Step Treatment conditions Alkali treatment 50° C., 10 seconds Mask material application 50° C., 2 minutes treatment Ultraviolet ray irradiation 10 minutes Catalyst application treatment 50° C., 5 minutes Reduction treatment 35° C., 4 minutes Electroless copper nickel plating 60° C., 5 minutes (Washing with water is performed as needed after each step)

Modifying Step

The resin article 410 and the resin article surface 420 are shown in 4a in FIG. 4. First, the resin article 410 was subjected to an alkali treatment. In 4b in FIG. 4, a modified resin article surface 430 of the resin article 410 resulting from the modifying step is shown. Specifically, the resin article 410 was immersed for 10 seconds in an aqueous solution of sodium hydroxide adjusted so as to be 50° C. and 0.90 mol/L, which is an alkali treatment solution used in a Cu—Ni plating solution set “AISL” available from JCU Corporation. Thereafter, the resin article 410 was washed with water.

Mask Material Applying Step (First Applying Step)

Next, after undergoing the alkali treatment, the resin article 410 was subjected to a mask material application treatment. In 4c in FIG. 4, the surface 440 of the resin article 410 to which the mask material has been applied, resulting from the mask material applying step, is shown. Specifically, the resin article 410 was immersed for 2 minutes at 50° C. using a conditioner solution used in the Cu—Ni plating solution set “AISL”, available from JCU Corporation. Thereafter, the resin article 410 was washed with water.

Ultraviolet Ray Irradiation Step

Next, the portion on which the plating layer was to be formed on the resin article 410 was irradiated with ultraviolet rays via a photomask in air. In 4d in FIG. 4, a region 450 selectively irradiated with ultraviolet rays is shown. The other region was not irradiated with ultraviolet rays. The ultraviolet ray irradiation conditions were as follows.

Low-voltage mercury lamp: UV-300 (primary wavelengths: 185 nm, 254 nm), available from Samco Corporation

Irradiation distance: 3.5 cm

Illuminance at irradiation distance of 3.5 cm: 5.40 mW/cm2 (254 nm), and 1.35 mW/cm2 (185 nm)

Irradiation time: 10 minutes

The cumulative exposure amount at this time was 1.35 mW/cm2×600 seconds=about 810 mJ/cm2.

Catalyst Applying Step (Second Applying Step)

Next, the resin article 410 irradiated with ultraviolet rays was subjected to a catalyst application treatment. As shown in 4e in FIG. 4, the electroless plating catalyst is applied to the surface of the resin article 410 that was irradiated with ultraviolet rays. The electroless plating catalyst binds to the region 450 irradiated with ultraviolet rays. In 4e in FIG. 4, a region 460 to which the electroless plating catalyst was applied is shown. Specifically, the resin article 410 was immersed for 5 minutes at 50° C. using an activator solution (product name: ELFSEED ES-300, available from JCU Corporation). At this time, the activator solution was used at three times the concentration specified by the manufacturer. Thereafter, the resin article 410 was washed with water. Thus, the catalyst ions were applied. Furthermore, the resin article 410 was immersed for 4 minutes at 35° C. using the accelerator solution (product name: ELFSEED ES-4, available from JCU Corporation). Thereafter, the resin article 410 was washed with water. Thus, the catalyst ions were reduced.

Electroless Plating Step

Next, the resin article 410 resulting from the reduction treatment was subjected to electroless copper nickel plating. Specifically, the resin article 410 was heated to 60° C. and immersed for 5 minutes using the electroless Cu—Ni plating solution (product name: AISL-520, available from JCU Corporation). Thereafter, the resin article 410 was washed with water.

A resin article 400 having a plating layer shown in 4f in FIG. 4 was produced using the treatments above. The resin article 400 having a plating layer was observed, and it was found that the plating layer 470 was formed on the region 450 irradiated with ultraviolet rays, but no plating layer was formed on the portion that was not irradiated with ultraviolet rays. Thus, it can be understood that the plating layer can be formed selectively with good reproducibility according to the method of Example 1.

Example 2

The resin article 410 having a plating layer was produced in a manner similar to that of Example 1, except for the fact that the resin article 410 was irradiated with ultraviolet rays for 7 minutes in the ultraviolet ray irradiation step. In Example 2 as well, the plating layer 470 was formed on the region 450 irradiated with ultraviolet rays and no plating layer was formed on the portion that was not irradiated with ultraviolet rays.

Example 3

The resin article having a plating layer 410 was produced in a manner similar to that of Example 1, except for the fact that the resin article 410 was irradiated with ultraviolet rays for 3 minutes in the ultraviolet ray irradiation step. In Example 3, the plating layer 480 was formed only on a portion of the region 450 irradiated with ultraviolet rays. Also, no plating layer was formed on the portion that was not irradiated with ultraviolet rays. In 4g in FIG. 4, the resin article 410 on which the plating layer 480 was formed in the present example is shown.

Example 4

The resin article 410 having a plating layer was produced in a manner similar to that of Example 1, except for the fact that the resin article 410 was irradiated with ultraviolet rays for 5 minutes in the ultraviolet ray irradiation step. In Example 4, the plating layer 490 was not formed in narrow parts of the region 450 irradiated with ultraviolet rays. Also, no plating layer was formed on the portion that was not irradiated with ultraviolet rays. In the present example, in 4h in FIG. 4, the resin article 410 on which the plating layer 490 was formed is shown.

Example 5

The resin article having a plating layer 410 was produced in a manner similar to that of Example 1, except for the fact that the resin article 410 was irradiated with ultraviolet rays for 15 minutes in the ultraviolet ray irradiation step. In Example 5, the plating layer was not sufficiently formed on the region 450 irradiated with ultraviolet rays. Also, no plating layer was formed on the portion that was not irradiated with ultraviolet rays.

As described above, it was confirmed that the plating layer is sufficiently deposited on the portion of the resin article selectively irradiated with ultraviolet rays by performing irradiation with ultraviolet rays for an appropriate amount of time. The inventor also found that if there is originally-present damage on the resin surface or the resin is damaged in a step of generating the plating layer, or the like, the plating layer tends to spread out in the form of spikes at the damaged portion. On the other hand, the inventor confirmed that the plating layer tends to withdraw inward from the boundary along recessions and protrusions caused by damage in the plating layer produced using the methods of Examples 1 and 2. Due to these characteristics, with the methods of Examples 1 and 2, it is possible to prevent the occurrence of defects such as a wiring pattern short circuiting.

Comparative Example 1

First, the resin article 410 was subjected to ultraviolet ray irradiation for 10 minutes using a procedure similar to that of Example 1. Thereafter, the resin article 410 irradiated with ultraviolet rays was subjected to an alkali treatment. Specifically, the resin article 410 was immersed for 2 minutes in an aqueous solution of sodium hydroxide adjusted so as to be 50° C. and 0.90 mol/L, which is an alkali treatment solution used in the Cu—Ni plating solution set “AISL”, available from JCU Corporation. Thereafter, the resin article 410 was washed with water.

Furthermore, the resin article 410 subjected to the alkali treatment was subjected to a conditioning treatment. Specifically, the resin article 410 was immersed for 2 minutes at 50° C. using a conditioner solution used in the Cu—Ni plating solution set “AISL”, available from JCU Corporation. At this time, the conditioner solution that was used was diluted to one-tenth the concentration designated by the maker. If the resin article is polyimide, the conditioner tends to remain in the portion that was not irradiated with ultraviolet rays due to the alkali treatment in the previous step. For this reason, the conditioner used was diluted in order to achieve selectivity by causing the conditioner to remain on the portion irradiated with ultraviolet rays and making it easier to rinse off the conditioner on the non-irradiated portion. Thereafter, the resin article 410 was washed with water. Next, the resin article 410 irradiated with ultraviolet rays was subjected to a catalyst application treatment. Specifically, the resin article 410 was immersed for 2 minutes at 50° C. using the activator solution (product name: AISL-ACT, available from JCU Corporation). Thereafter, the resin article 410 was washed with water. Furthermore, the resin article 410 was immersed for 2 minutes at 40° C. using the accelerator solution (product name: acceleration treatment solution for AISL-520, available from JCU Corporation). Thereafter, the resin article 410 was washed with water. Thus, a catalyst ion reduction treatment was performed. Thereafter, electroless copper nickel plating was performed in a manner similar to that of Example 1. In Comparative Example 1, the plating layer was formed on both the portion irradiated with ultraviolet rays and the portion that was not irradiated with ultraviolet rays. Table 2 shows the steps carried out in Comparative Example 1.

TABLE 2 Step Treatment Conditions Ultraviolet ray irradiation 10 minutes Alkali treatment 50° C., 2 minutes Conditioning treatment 50° C., 2 minutes Catalyst application treatment 50° C., 2 minutes Reduction treatment 40° C., 2 minutes Electroless copper nickel 60° C., 5 minutes. plating (Washing with water was performed as needed after each step)

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2014-261209, filed Dec. 24, 2014, which is hereby incorporated by reference herein in its entirety.

Claims

1. A method for manufacturing a resin article having a plating layer, obtained by forming a plating layer on a portion of a surface of a resin article, the method comprising:

treating the surface of the resin article with a mask material solution;
irradiating a portion of the surface of the resin article selectively with ultraviolet rays such that it is possible to apply an electroless plating catalyst to the portion of the surface of the resin article;
applying the electroless plating catalyst to the portion of the surface of the resin article irradiated with ultraviolet rays; and
forming a plating layer on the portion of the surface of the resin article irradiated with ultraviolet rays, using electroless plating.

2. The method for manufacturing a resin article having a plating layer according to claim 1, further comprising modifying the surface of the resin article before the treating.

3. The method for manufacturing a resin article having a plating layer according to claim 2, wherein

the modifying further includes treating the resin article with an alkali solution.

4. The method for manufacturing a resin article having a plating layer according to claim 3, wherein

a chemical adsorption group is produced on the surface of the resin article due to the treatment with the alkali solution.

5. The method for manufacturing a resin article having a plating layer according to claim 1, wherein

the surface of the resin article includes at least one of an imide bond, an amide bond, and an ester bond.

6. The method for manufacturing a resin article having a plating layer according to claim 1, wherein

the surface of the resin article includes polyimide resin or polyamide resin.

7. The method for manufacturing a resin article having a plating layer according to claim 1, wherein

the mask material includes a cation polymer.

8. The method for manufacturing a resin article having a plating layer according to claim 1, wherein

in the irradiating, the portion of the surface of the resin article is irradiated with ultraviolet rays of 243 nm or less.

9. The method for manufacturing a resin article having a plating layer according to claim 1, wherein

the irradiating is performed in an atmosphere including at least one of oxygen and ozone.

10. The method for manufacturing a resin article having a plating layer according to claim 1, wherein

the applying includes bringing an electroless plating catalyst solution or an electroless plating catalyst ion solution into contact with the surface of the resin article.

11. The method for manufacturing a resin article having a plating layer according to claim 1, wherein

the applying includes bringing an electroless plating catalyst ion solution into contact with the surface of the resin article and reducing the electroless plating catalyst ions, and the electroless plating catalyst ions are palladium complexes having a positive charge in at least a portion thereof.

12. A resin article having a plating layer, manufactured using a method comprising:

treating a surface of a resin article with a mask material solution;
irradiating a portion of the surface of the resin article selectively with ultraviolet rays such that it is possible to apply an electroless plating catalyst to the portion of the surface of the resin article;
applying the electroless plating catalyst to the portion of the surface of the resin article irradiated with ultraviolet rays; and
forming a plating layer on the portion of the surface of the resin article irradiated with ultraviolet rays, using electroless plating.
Patent History
Publication number: 20160186323
Type: Application
Filed: Dec 22, 2015
Publication Date: Jun 30, 2016
Inventor: Taisuke IWASHITA (Saitama-ken)
Application Number: 14/978,354
Classifications
International Classification: C23C 18/16 (20060101); C23C 18/18 (20060101);