JP2022138815A - Plating method and wiring board obtained using the same - Google Patents
Plating method and wiring board obtained using the same Download PDFInfo
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- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- XECAHXYUAAWDEL-UHFFFAOYSA-N acrylonitrile butadiene styrene Chemical compound C=CC=C.C=CC#N.C=CC1=CC=CC=C1 XECAHXYUAAWDEL-UHFFFAOYSA-N 0.000 description 2
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- HRXKRNGNAMMEHJ-UHFFFAOYSA-K trisodium citrate Chemical compound [Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O HRXKRNGNAMMEHJ-UHFFFAOYSA-K 0.000 description 2
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Abstract
Description
本発明は、めっき処理方法、及びその方法を用いて得られる配線板に関する。 The present invention relates to a plating method and a wiring board obtained using the method.
近年、電子機器の軽薄短小化、高性能化、形状の多様化が進んでいる。また、近年はＩｏＴ（Ｉｎｔｅｒｎｅｔ ｏｆ Ｔｈｉｎｇｓ）時代であるために種々のセンサが用いられ、配線回路を形成する基材が平板形状だと適応が難しい場合がある。そのため、小型で複雑形状の基材の表面に配線回路を形成できる立体回路成形部品（ＭＩＤ：Ｍｏｌｄｅｄ Ｉｎｔｅｒｃｏｎｎｅｃｔｅｄ Ｄｅｖｉｃｅ）が、通信、医療、及び自動車等の様々な産業分野で今後の潮流になると予測される。こうした背景から、今後の電子機器においては、構成する配線板の配線に関して更なる微細化が求められると共に、当該配線と配線基材との密着性の更なる向上が求められている。 In recent years, electronic devices have become lighter, thinner, shorter and smaller, have higher performance, and have diversified shapes. Moreover, in recent years, various sensors have been used due to the age of IoT (Internet of Things), and in some cases, it is difficult to adapt such sensors if the base material forming the wiring circuit is in the form of a flat plate. Therefore, three-dimensional circuit molded parts (MID: Molded Interconnected Device), which can form a wiring circuit on the surface of a small and complicated-shaped base material, are expected to become a trend in various industrial fields such as communication, medical care, and automobiles in the future. be. Against this background, in future electronic devices, there is a demand for further miniaturization of the wiring on the wiring board that constitutes it, as well as for further improvement in adhesion between the wiring and the wiring substrate.
配線基材の原料には、信号の伝送損失を低減すべく、低誘電率である樹脂材料が主に用いられている。そのため、樹脂材の表面に金属からなる配線（導体層）を形成するに際しては、主に無電解めっきが使用される。しかしながら、無電解めっき処理を行って、樹脂材の表面に導体層を形成した場合には、当該樹脂材と当該導体層との密着性が不十分となりやすい。このとき、樹脂材の表面をエッチング液（従来の過マンガン酸カリウムやマンガン酸ナトリウムや、近年の硫酸一過酸化水素系薬液等）を用いてエッチングすることにより粗面化し、アンカー効果を利用して当該樹脂材と当該導体層との密着性を得る従来の手法では、当該樹脂材の表面平滑度が低下し、微細な配線パターンを精度よく形成することができないといった問題が生じる。また、アンカー効果を利用した従来の手法を経て得られる導体層は、その表面粗度も大きくなり、１ＧＨｚ以上の高周波信号を伝送した際に表皮効果の影響が現われて伝送特性の低下を招くおそれがある。表面粗度の大きな導体層を電子機器に用いた場合には、電気的特性の向上を図ることができないといった問題が生じてしまう。 A resin material having a low dielectric constant is mainly used as a raw material for the wiring substrate in order to reduce signal transmission loss. Therefore, electroless plating is mainly used to form metal wiring (conductor layer) on the surface of the resin material. However, when electroless plating is performed to form a conductor layer on the surface of a resin material, adhesion between the resin material and the conductor layer tends to be insufficient. At this time, the surface of the resin material is roughened by etching with an etchant (conventional potassium permanganate or sodium manganate, recent sulfuric acid hydrogen monoxide chemicals, etc.), and the anchor effect is utilized. In the conventional method of obtaining adhesion between the resin material and the conductor layer by means of a method, the surface smoothness of the resin material is deteriorated, resulting in a problem that a fine wiring pattern cannot be formed with high precision. In addition, the conductor layer obtained through the conventional method using the anchor effect has a large surface roughness, and when a high frequency signal of 1 GHz or higher is transmitted, the effect of the skin effect appears, which may lead to deterioration of transmission characteristics. There is When a conductor layer having a large surface roughness is used in an electronic device, there arises a problem that the electrical characteristics cannot be improved.
上述した問題に対して、レーザーダイレクトストラクチャリング（ＬＤＳ：Ｌａｓｅｒ Ｄｉｒｅｃｔ Ｓｔｒｕｃｔｕｒｉｎｇ）工法が実用化されている。ＬＤＳ工法では、配線回路形成用の樹脂材として、レーザー照射により活性化される有機金属化合物（金属錯体）を含んだＬＤＳ添加剤を配合したものを用いる。そして、現行においては当該樹脂材の配線形成予定箇所に赤外光のレーザーを照射することで、レーザー照射領域に存在するこの有機金属化合物を、表面に露出させると共に触媒として活性化させる。その結果、配線形成予定領域に選択的に無電解めっき被膜を形成することができる。さらに、ＬＤＳ工法では、樹脂材にレーザー処理を施すことにより、この配線形成予定領域の表面に粗化処理を施すことができる。そのため、アンカー効果により、配線となるめっき被膜を当該樹脂材の表面に強固に固定させることが可能となる。なお、ＬＤＳ工法に関する技術としては、例えば特許文献１や特許文献２等に開示がされている。ＬＤＳ工法は、レーザー処理を採用するため、立体配線板であっても、レーザーを走査して微細で複雑な配線を高精度で形成することが可能である。 A laser direct structuring (LDS) construction method has been put to practical use to address the above-described problems. In the LDS construction method, as a resin material for forming a wiring circuit, a resin material mixed with an LDS additive containing an organic metal compound (metal complex) activated by laser irradiation is used. At present, by irradiating an infrared laser onto a portion of the resin material where wiring is to be formed, the organometallic compound existing in the laser irradiation region is exposed on the surface and activated as a catalyst. As a result, it is possible to selectively form an electroless plating film on the wiring formation planned region. Furthermore, in the LDS method, the surface of the wiring formation planned region can be roughened by laser processing the resin material. Therefore, due to the anchor effect, it is possible to firmly fix the plated film, which becomes the wiring, to the surface of the resin material. Techniques related to the LDS construction method are disclosed, for example, in Patent Document 1, Patent Document 2, and the like. Since the LDS method employs laser processing, even a three-dimensional wiring board can be scanned with a laser to form fine and complicated wiring with high precision.
しかし、ＬＤＳ工法では、樹脂材に配合されたＬＤＳ添加剤を表出させなければならず、その分余計にレーザー照射を行う必要がある。そのため、ＬＤＳ工法を用いた場合には、めっき被処理面の粗さが大きくなってしまい、最終的に得られる配線板が高周波回路用として適さなくなるおそれがある。また、ＬＤＳ工法では、樹脂材にＬＤＳ添加剤を配合する必要があるため、このＬＤＳ添加剤の種類によっては、当該樹脂材の特性（機械的強度等）に悪影響が生じるおそれがある。さらに、ＬＤＳ工法では、用いるＬＤＳ添加剤が特殊であるため、めっき工程の管理が煩雑化する場合もある。 However, in the LDS construction method, the LDS additive blended in the resin material must be exposed, and it is necessary to perform additional laser irradiation accordingly. Therefore, when the LDS method is used, the roughness of the surface to be plated increases, and there is a possibility that the finally obtained wiring board may not be suitable for use in high frequency circuits. Moreover, in the LDS construction method, it is necessary to add an LDS additive to the resin material, so depending on the type of the LDS additive, there is a risk that the characteristics (mechanical strength, etc.) of the resin material will be adversely affected. Furthermore, in the LDS method, the LDS additive used is special, so the management of the plating process may become complicated.
以上のことから、本発明の課題は、樹脂材と導体層との密着性を高めると共に処理コストを抑えながらも、高周波回路用として好適な導体層を安定的に形成することのできるめっき方法及びそれを用いて得られる配線板を提供することにある。 In view of the above, an object of the present invention is to provide a plating method and a plating method that can stably form a conductor layer suitable for high-frequency circuits while increasing the adhesion between a resin material and a conductor layer and suppressing the processing cost. An object of the present invention is to provide a wiring board obtained by using it.
本発明者は、鋭意研究を行った結果、以下のめっき方法、及びその方法を用いて得られる配線板を採用することで上記課題を達成するに到った。 As a result of intensive research, the inventors have achieved the above object by adopting the following plating method and a wiring board obtained by using the method.
本発明に係るめっき方法は、樹脂材表面の紫外線照射箇所にのみ導体層を形成するめっき方法であって、当該樹脂材のレーザー顕微鏡を用いた非接触式の測定による算術平均高さＳａが５００ｎｍ以下であるめっき被処理面に対して形状変形が生じない程度の紫外線を照射する紫外線照射工程と、当該紫外線照射工程を行った後、当該樹脂材のめっき被処理面に対して２５～６０℃の脱脂剤を５分間～１０分間接触させて脱脂を行う脱脂工程とを含み、その後、めっき処理を行い当該導体層を形成することを特徴とする。 The plating method according to the present invention is a plating method in which a conductor layer is formed only on a portion irradiated with ultraviolet rays on the surface of a resin material, and the arithmetic mean height Sa of the resin material measured by non-contact measurement using a laser microscope is 500 nm. After performing the following ultraviolet irradiation step of irradiating the surface to be plated with ultraviolet rays to the extent that shape deformation does not occur, and the ultraviolet irradiation step, the surface to be plated of the resin material is 25 to 60 ° C. and a degreasing step of contacting with a degreasing agent for 5 to 10 minutes to perform degreasing, and then performing plating to form the conductor layer.
本発明に係るめっき方法は、前記紫外線照射工程の直前と直後における、前記めっき被処理面の前記算術平均高さＳａの差を１０ｎｍ～１０００ｎｍとすることが好ましい。 In the plating method according to the present invention, it is preferable that the difference in the arithmetic mean height Sa of the surface to be plated immediately before and after the ultraviolet irradiation step is 10 nm to 1000 nm.
本発明に係るめっき方法は、前記脱脂工程の直前と直後における、前記めっき被処理面の前記算術平均高さＳａの差を３ｎｍ～１０ｎｍとすることが好ましい。 In the plating method according to the present invention, it is preferable that the difference in the arithmetic mean height Sa of the surface to be plated immediately before and after the degreasing step is 3 nm to 10 nm.
本発明に係るめっき方法において、前記めっき処理は、前記めっき被処理面に対して、塩化第一スズを主成分として含む溶液を３０秒間～３分間接触させてスズイオンを吸着させるセンシタイジング処理工程と、当該センシタイジング処理工程の後、当該めっき被処理面に対して、塩化パラジウムを主成分として含む溶液を３０秒間～３分間接触させてパラジウムを析出させるアクティベーティング処理工程と、当該アクティベーティング処理工程の後、当該めっき被処理面にめっきにより前記導体層を形成する導体層形成工程とを含むことが好ましい。 In the plating method according to the present invention, the plating treatment includes a sensitizing treatment step in which a solution containing stannous chloride as a main component is brought into contact with the surface to be plated for 30 seconds to 3 minutes to adsorb tin ions. and, after the sensitizing treatment step, an activating treatment step of depositing palladium by contacting the surface to be plated with a solution containing palladium chloride as a main component for 30 seconds to 3 minutes; It is preferable to include a conductor layer forming step of forming the conductor layer on the surface to be plated by plating after the baking treatment step.
本発明に係るめっき方法において、前記導体層形成工程は、前記めっき被処理面に厚さ０．１～５μｍのニッケル－リン層を形成した後に、当該ニッケル－リン層の表面に厚さ１０～３５μｍの銅層を形成することが好ましい。 In the plating method according to the present invention, in the conductor layer forming step, after forming a nickel-phosphorus layer having a thickness of 0.1 to 5 μm on the surface to be plated, It is preferred to form a copper layer of 35 μm.
本発明に係るめっき方法は、前記導体層形成工程で用いるめっき浴の浴温が５０℃～８０℃であることが好ましい。 In the plating method according to the present invention, the bath temperature of the plating bath used in the conductor layer forming step is preferably 50.degree. C. to 80.degree.
本発明に係るめっき方法は、前記樹脂材がエポキシ樹脂材、液晶ポリマー材、ポリフェニレンサルファイド樹脂材、又はＡＢＳ樹脂材であることが好ましい。 In the plating method according to the present invention, the resin material is preferably an epoxy resin material, a liquid crystal polymer material, a polyphenylene sulfide resin material, or an ABS resin material.
本発明に係る配線板は、上述しためっき方法を用いて得られることを特徴とする。 A wiring board according to the present invention is characterized by being obtained by using the plating method described above.
本発明によれば、樹脂材と金属からなる配線との密着性を高めると共に処理コストを抑えながらも、高周波回路用として好適な配線を安定的に形成することができる。 According to the present invention, it is possible to stably form wiring suitable for high-frequency circuits while increasing adhesion between resin material and wiring made of metal and suppressing processing costs.
以下、本発明に係るめっき方法、及びその方法を用いて得られる配線板の実施の形態について説明する。なお、本発明の態様は、以下に示す実施の形態に限定されるものではない。 A plating method according to the present invention and an embodiment of a wiring board obtained by using the method will be described below. In addition, the aspect of this invention is not limited to embodiment shown below.
Ａ．本発明に係るめっき方法
本発明に係るめっき方法は、樹脂材表面の紫外線照射箇所にのみ導体層を形成するめっき方法である。そして、「当該樹脂材のレーザー顕微鏡を用いた非接触式の測定による算術平均高さＳａ（ＩＳＯ２５１７８に規定される面粗さパラメータ。以下同様。）が５００ｎｍ以下であるめっき被処理面に対して形状変形が生じない程度の紫外線を照射する紫外線照射工程」と、「当該紫外線照射工程を行った後、当該樹脂材のめっき被処理面に対して２５～６０℃の脱脂剤を５分間～１０分間接触させて脱脂を行う脱脂工程」を必須としている。その後、めっき処理を行い当該導体層を形成する。以下に、本発明のめっき前処理としての、当該紫外線照射工程と当該脱脂工程について説明する。
A. Plating Method According to the Present Invention The plating method according to the present invention is a plating method in which a conductor layer is formed only on a portion irradiated with ultraviolet rays on the surface of a resin material. Then, "Arithmetic mean height Sa (surface roughness parameter specified in ISO 25178; the same shall apply hereinafter) of the resin material measured by non-contact measurement using a laser microscope is 500 nm or less for the surface to be plated Ultraviolet irradiation step of irradiating ultraviolet rays to the extent that shape deformation does not occur” and “After performing the ultraviolet irradiation step, the surface of the resin material to be plated is subjected to a degreasing agent at 25 to 60 ° C. for 5 minutes to 10 minutes. A degreasing process that degreases by contacting for minutes is essential. After that, plating is performed to form the conductor layer. The ultraviolet irradiation step and the degreasing step as the plating pretreatment of the present invention will be described below.
Ａ－１．めっき前処理
以下、紫外線照射工程と脱脂工程とに分けて説明する。
A-1. Plating Pretreatment Hereinafter, the ultraviolet irradiation process and the degreasing process will be separately described.
＜紫外線照射工程について＞
本発明に係るめっき方法は、アンカー効果を得るためのエッチング処理工程や触媒付与を促進させるための界面活性剤吸着工程の代わりに、めっき被処理面に対して形状変形が生じない程度の紫外線を照射する工程を有するものである。本発明に係るめっき方法は、この紫外線照射工程において、導体層を形成する樹脂材のめっき被処理面に紫外線を照射することで、当該めっき被処理面を親水性に改質する。めっき被処理面の親水性を向上させることで、当該めっき被処理面に触媒として機能し得る金属を吸着させやすくなり、当該樹脂材と当該導体層との界面における密着力を化学的に向上させることが可能となる。
<About the UV irradiation process>
In the plating method according to the present invention, instead of an etching treatment step for obtaining an anchor effect and a surfactant adsorption step for promoting the application of a catalyst, ultraviolet rays are applied to the surface to be plated to such an extent that shape deformation does not occur. It has a step of irradiating. In the ultraviolet irradiation step, the plating method according to the present invention irradiates the surface to be plated of the resin material forming the conductor layer with ultraviolet rays, thereby modifying the surface to be plated to be hydrophilic. By improving the hydrophilicity of the surface to be plated, it becomes easier for the surface to be plated to adsorb a metal that can function as a catalyst, chemically improving the adhesion at the interface between the resin material and the conductor layer. becomes possible.
ここで、上述した、樹脂材の表面を親水性に変化させるための改質に関して説明する。この改質は、紫外線の照射により、樹脂材のめっき被処理面の構造特性や機能性を向上させるものである。具体的には、樹脂材に対する適切な波長の紫外線の照射により、樹脂材表面の高分子の化学結合が切断され、当該樹脂材表面に酸化に伴う官能基（ヒドロキシル基（－ＯＨ）やカルボキシル基（－ＣＯＯＨ）等の親水性基）が生成されることを言う。この改質により、無電解めっきを行う場合に、当該樹脂材に対して触媒イオンを選択的に吸着させることが可能となる。 Here, the modification for making the surface of the resin material hydrophilic will be described. This modification improves the structural properties and functionality of the surface of the resin material to be plated by irradiating it with ultraviolet rays. Specifically, by irradiating the resin material with ultraviolet light of an appropriate wavelength, the chemical bonds of the polymer on the surface of the resin material are cut, and the functional groups (hydroxyl group (-OH) and carboxyl group) associated with oxidation are formed on the surface of the resin material. It means that a hydrophilic group such as (-COOH) is generated. This modification makes it possible to selectively adsorb catalyst ions to the resin material when performing electroless plating.
ところで、本発明に係るめっき方法において、樹脂材に照射する紫外線の波長域は、当該樹脂材の材質にもよるが、１５０～４００ｎｍの範囲で適宜選択することができる。樹脂材のめっき被処理面に対して当該樹脂材の材質に適切な波長の紫外線を照射することによって当該めっき被処理面が酸化され、親水性基が付与される。一般的に、この親水性基が多くなるほど、親水性が増大するとされる。 By the way, in the plating method according to the present invention, the wavelength range of the ultraviolet rays irradiated to the resin material can be appropriately selected within the range of 150 to 400 nm, depending on the material of the resin material. By irradiating the surface of the resin material to be plated with ultraviolet rays having a wavelength appropriate for the material of the resin material, the surface to be plated is oxidized and hydrophilic groups are imparted. In general, it is believed that the greater the number of hydrophilic groups, the greater the hydrophilicity.
なお、本発明に係るめっき方法において、上述した紫外線の発生源は、特に限定されるものではなく、ＵＶランプ、気体レーザー、固体レーザー等から適宜選択して用いることができる。ここで、気体レーザーとしては、例えばＫｒＦレーザーやＡｒＦレーザー等のエキシマレーザーが挙げられる。また、固体レーザーとしては、例えばＹＡＧレーザーが挙げられる。参考までに、エキシマレーザーは、波長が短いため細密な加工を行うことができる。さらに、走査性にも優れるため、樹脂材の形状が複雑な三次元形状であったとしても、その樹脂材の表面に所謂立体配線を形成することが他の紫外線発生源に比べて容易となる。 In addition, in the plating method according to the present invention, the above-mentioned ultraviolet light generation source is not particularly limited, and can be appropriately selected and used from UV lamps, gas lasers, solid-state lasers, and the like. Here, examples of gas lasers include excimer lasers such as KrF lasers and ArF lasers. Moreover, as a solid-state laser, for example, a YAG laser can be used. For reference, the excimer laser has a short wavelength and can perform fine processing. Furthermore, since the scanability is also excellent, even if the shape of the resin material is a complicated three-dimensional shape, it is easier to form a so-called three-dimensional wiring on the surface of the resin material compared to other ultraviolet generation sources. .
また、本発明に係るめっき方法において、上述した樹脂材としては紫外線の照射によって当該樹脂材のめっき被処理面が改質し得るものであれば用いることができる。例えば、当該樹脂材として、ＬＣＰ（液晶ポリマー）、ＰＰＳ（ポリフェニレンサルファイト樹脂）、ＰＯＭ（ポリアセタール）、ＰＣ（ポリカーボネート）、ＰＭＭＡ（ポリメチルメタアクリレート）、ＰＥＴ（ポリエチレンテレフタレート）、ＰＥ（ポリエチレン）、ＰＰ（ポリプロピレン）、ＰＳ（ポリスチレン）、ＰＶＣ（ポリ塩化ビニル）、ＡＢＳ（アクリロニトリル・ブタジエン・スチレンポリマー）等の熱可塑性樹脂や、ＰＥ（フェノール樹脂）、ＥＰ（エポキシ樹脂）等の熱硬化性樹脂を用いることができる。ここに挙げた樹脂材の中でも、配線基板材料としての有用性や高周波用配線基板への適合性を考慮すると、特にエポキシ樹脂材、液晶ポリマー材、ポリフェニレンサルファイド樹脂材、又はＡＢＳ樹脂材を用いることが好ましい。 In the plating method according to the present invention, any resin material can be used as long as the surface to be plated of the resin material can be modified by irradiation with ultraviolet rays. For example, the resin material includes LCP (liquid crystal polymer), PPS (polyphenylene sulfite resin), POM (polyacetal), PC (polycarbonate), PMMA (polymethyl methacrylate), PET (polyethylene terephthalate), PE (polyethylene), Thermoplastic resins such as PP (polypropylene), PS (polystyrene), PVC (polyvinyl chloride), ABS (acrylonitrile-butadiene-styrene polymer), and thermosetting resins such as PE (phenolic resin) and EP (epoxy resin) can be used. Among the resin materials listed here, epoxy resin material, liquid crystal polymer material, polyphenylene sulfide resin material, or ABS resin material should be used in consideration of usefulness as a wiring board material and suitability for high-frequency wiring boards. is preferred.
そして、本発明に係るめっき方法において、用いる樹脂材は、めっき被処理面の算術平均高さＳａが５００ｎｍ以下となるものである。この条件を満たすめっき被処理面に対して形状変形が生じない程度の紫外線を照射することで、当該めっき被処理面を親水性に改質しながらも、当該めっき被処理面をナノメートルオーダーの微細構造に維持することができる。めっき被処理面の表面平滑度がこの水準であれば、当該めっき被処理面に導体層を形成した際に当該導体層の高周波領域における伝送損失が小さくなる。なお、当該導体層において、高周波領域における伝送損失抑制の安定化や、１０ＧＨｚ以上の超高周波領域での伝送損失の改善を図る場合には、当該めっき被処理面の算術平均高さＳａは３００ｎｍ以下であることがより好ましく、６０ｎｍ以下であることがさらに好ましい。当該めっき被処理面の算術平均高さＳａが６０ｎｍ以下となる高周波回路であれば、次世代通信規格「５Ｇ」、「６Ｇ」の高周波を用いた電子機器等にも好適に用いることが可能となる。 In the plating method according to the present invention, the resin material used is such that the arithmetic mean height Sa of the surface to be plated is 500 nm or less. By irradiating the surface to be plated with ultraviolet light to such an extent that shape deformation does not occur on the surface to be plated that satisfies this condition, the surface to be plated is changed to be hydrophilic while improving the surface to be plated to nanometer order. Fine structure can be maintained. If the surface smoothness of the surface to be plated is at this level, when a conductor layer is formed on the surface to be plated, the transmission loss of the conductor layer in the high frequency region becomes small. In the conductor layer, when stabilizing transmission loss suppression in a high frequency region or improving transmission loss in an ultra-high frequency region of 10 GHz or higher, the arithmetic mean height Sa of the plated surface is 300 nm or less. is more preferably 60 nm or less. A high-frequency circuit in which the arithmetic mean height Sa of the surface to be plated is 60 nm or less can be suitably used for electronic devices using high-frequency waves of next-generation communication standards "5G" and "6G". Become.
本発明に係るめっき方法では、樹脂材のめっき被処理面に対する紫外線の照射条件を、当該めっき被処理面に形状変形が生じない程度としている。しかし、高速電送に対応した回路用として好適な導体層を形成することと、樹脂材と当該導体層との密着性を高周波回路基板に求められる水準まで向上させることを考慮すると、紫外線照射工程の直前と直後における、めっき被処理面の算術平均高さＳａの差を１０ｎｍ～１０００ｎｍとすることが好ましい。ここで、紫外線照射工程の直前と直後における、めっき被処理面の算術平均高さＳａの差が１０ｎｍ未満の場合には、当該めっき被処理面を十分に親水性に改質させることができず、樹脂材と導体層との密着性を安定的に高めることができない。一方、めっき被処理面の算術平均高さＳａの差が１０００ｎｍを超える場合には、当該めっき被処理面に形成した導体層において、高周波信号を伝送する際にシグナル電流に大きな伝送損失が発生し好ましくない。このめっき被処理面の算術平均高さＳａの差の上限値は、上述した「高速電送に対応した回路用として好適な導体層を形成する」効果を安定的且つ十分に得る上で、２００ｎｍであることがより好ましく、６０ｎｍであることがさらに好ましい。 In the plating method according to the present invention, the conditions for irradiating the surface of the resin material to be plated with the ultraviolet rays are such that the surface to be plated is not deformed. However, considering the formation of a conductor layer suitable for circuits compatible with high-speed transmission and the improvement of the adhesion between the resin material and the conductor layer to the level required for high-frequency circuit boards, the ultraviolet irradiation process The difference in arithmetic mean height Sa of the surface to be plated immediately before and after is preferably 10 nm to 1000 nm. Here, if the difference in the arithmetic mean height Sa of the plated surface immediately before and after the ultraviolet irradiation step is less than 10 nm, the plated surface cannot be sufficiently modified to be hydrophilic. , the adhesion between the resin material and the conductor layer cannot be stably enhanced. On the other hand, when the difference in the arithmetic mean height Sa of the plated surface exceeds 1000 nm, a large transmission loss occurs in the signal current when transmitting a high-frequency signal in the conductor layer formed on the plated surface. I don't like it. The upper limit of the difference in the arithmetic mean height Sa of the surface to be plated is 200 nm in order to stably and sufficiently obtain the effect of "forming a conductive layer suitable for circuits compatible with high-speed electrical transmission". It is more preferably 60 nm, more preferably 60 nm.
＜脱脂工程について＞
本発明に係るめっき方法は、上述した紫外線照射工程を行った後に、樹脂材のめっき被処理面に対して以下に示す条件の脱脂工程を行うことで、当該めっき被処理面の表面粗さを極力変化させずに、樹脂材と導体層との界面における密着力を物理的にも向上させることができる。すなわち、上述した紫外線照射工程で樹脂材のめっき被処理面に紫外線を照射すると、当該めっき被処理面において、分子間結合の分子鎖を切断する光分解加工が施される。その後、本発明の脱脂工程を行うことで、この光分解加工を行った際に生じる加工残渣が取り除かれて、当該めっき被処理面にアンカー効果を有するナノメートルオーダーの微細凹凸を備える表面が形成される。その結果、当該めっき被処理面の表面粗さの増大を最小限に抑えつつ、当該樹脂材と当該導体層との密着性を必要十分に確保することが可能となる。
<Regarding the degreasing process>
In the plating method according to the present invention, after performing the ultraviolet irradiation step described above, the surface to be plated of the resin material is subjected to a degreasing step under the conditions shown below, thereby reducing the surface roughness of the surface to be plated. It is possible to physically improve the adhesion force at the interface between the resin material and the conductor layer without changing it as much as possible. That is, when the surface to be plated of the resin material is irradiated with ultraviolet rays in the ultraviolet irradiation step described above, the surface to be plated is subjected to a photodecomposition process that cuts the molecular chains of the intermolecular bonds. After that, by performing the degreasing step of the present invention, the processing residue generated when this photodecomposition processing is performed is removed, and a surface with nanometer-order fine unevenness having an anchor effect is formed on the surface to be plated. be done. As a result, it is possible to ensure necessary and sufficient adhesion between the resin material and the conductor layer while minimizing an increase in the surface roughness of the surface to be plated.
本発明の脱脂工程は、樹脂材のめっき被処理面に対して２５～６０℃の脱脂剤を５分間～１０分間接触させて脱脂を行うものである。本発明の脱脂工程で用いる脱脂剤は特に限定されないが、例えば、水酸化ナトリウム溶液を含むアルカリ脱脂剤や酸性脱脂剤等の公知の脱脂剤を適宜採用することができる。ここで、脱脂剤の温度が２５℃未満又は樹脂材の表面に脱脂剤を接触させる時間が５分間未満の場合には、上述した紫外線照射工程で生じた加工残渣を十分に取り除くことができず、樹脂材と導体層との密着性を安定的に向上させることができない。また、当該樹脂材に付着している油脂や汚れ等を完全に取り除くことも困難であるため、後工程において金属触媒の吸着力を向上させることができず、当該めっき被処理面にめっきを十分に析出させることができない。一方、脱脂剤の温度が６０℃を超え又は樹脂材の表面に脱脂剤を接触させる時間が１０分間を超える場合には、樹脂材のめっき被処理面のみならず全面が親水化してしまい選択めっき性の低下を招くおそれがある。なお、本発明の脱脂工程において、脱脂剤を樹脂材の表面に接触させる方法は特に限定されず、浸漬法や噴霧法を採用することができる。 In the degreasing step of the present invention, the surface of the resin material to be plated is degreased by contacting the surface to be plated with a degreasing agent at 25 to 60° C. for 5 to 10 minutes. Although the degreasing agent used in the degreasing step of the present invention is not particularly limited, for example, a known degreasing agent such as an alkaline degreasing agent containing a sodium hydroxide solution or an acidic degreasing agent can be appropriately employed. Here, if the temperature of the degreasing agent is less than 25° C. or the time that the degreasing agent is brought into contact with the surface of the resin material is less than 5 minutes, the processing residue generated in the above-described ultraviolet irradiation step cannot be sufficiently removed. , the adhesion between the resin material and the conductor layer cannot be stably improved. In addition, since it is difficult to completely remove grease, dirt, etc. adhering to the resin material, the adsorption power of the metal catalyst cannot be improved in the post-process, and the plating treatment surface cannot be sufficiently plated. cannot be precipitated on On the other hand, when the temperature of the degreasing agent exceeds 60° C. or the time for which the degreasing agent is brought into contact with the surface of the resin material exceeds 10 minutes, not only the surface to be plated but also the entire surface of the resin material becomes hydrophilic, resulting in selective plating. may lead to deterioration of sexuality. In the degreasing step of the present invention, the method of bringing the degreasing agent into contact with the surface of the resin material is not particularly limited, and a dipping method or a spraying method can be employed.
また、本発明に係るめっき方法では、脱脂工程の直前と直後における、樹脂材のめっき被処理面の算術平均高さＳａの差を３ｎｍ～１０ｎｍとすることが好ましい。樹脂材のめっき被処理面に対してこの条件を満たすように脱脂剤を接触させることで、樹脂材と導体層との密着性を十分に確保して、高速電送に対応した回路用として好適な導体層をより安定的に形成することが可能となる。ここで、脱脂工程の直前と直後における、当該めっき被処理面の算術平均高さＳａの差が３ｎｍ未満の場合には、樹脂材と導体層との密着強度の向上を必要十分に図れなくなってしまう。一方、当該めっき被処理面の算術平均高さＳａの差が１０ｎｍを超える場合には、当該めっき被処理面に形成した導体層は、高周波シグナルへの表皮効果の影響が顕著となり、伝送信号の遅延を引き起こすおそれがある。 Further, in the plating method according to the present invention, the difference in arithmetic mean height Sa of the surface of the resin material to be plated immediately before and after the degreasing process is preferably 3 nm to 10 nm. By bringing the degreasing agent into contact with the plated surface of the resin material so as to satisfy this condition, sufficient adhesion between the resin material and the conductor layer is secured, making it suitable for circuits compatible with high-speed electric transmission. It becomes possible to form a conductor layer more stably. Here, if the difference in the arithmetic mean height Sa of the plated surface immediately before and after the degreasing process is less than 3 nm, the adhesion strength between the resin material and the conductor layer cannot be sufficiently improved. put away. On the other hand, when the difference in the arithmetic mean height Sa of the plated surface exceeds 10 nm, the conductor layer formed on the plated surface is significantly affected by the skin effect on the high-frequency signal, and the transmission signal is reduced. May cause delays.
以上のことから、本発明に係るめっき方法は、上述しためっき前処理を採用することで、ＬＤＳ工法のように特殊なＬＤＳ添加剤を用いなくとも、樹脂材と導体層とが所望する密着強度を維持しつつ、高精度にパターニングされた回路配線を形成するのに必要な選択めっき性を向上させることが可能となる。さらに、上述しためっき前処理を採用することで、処理工程の簡素化も図ることができる。 From the above, the plating method according to the present invention adopts the above-described plating pretreatment, so that the desired adhesion strength between the resin material and the conductor layer can be obtained without using a special LDS additive as in the LDS method. While maintaining the above, it is possible to improve the selective plating properties necessary for forming circuit wiring patterned with high precision. Furthermore, by adopting the above-described plating pretreatment, it is possible to simplify the treatment process.
次に、本発明に係るめっき方法は、めっき処理として、「樹脂材の表面に対して、塩化第一スズを主成分として含む溶液を３０秒間～３分間接触させてスズイオンを吸着させるセンシタイジング処理工程」と、「当該センシタイジング処理工程の後、当該樹脂材のめっき被処理面に対して、塩化パラジウムを主成分として含む溶液を３０秒間～３分間接触させてパラジウムを析出させるアクティベーティング処理工程」と、「当該アクティベーティング処理工程の後、当該樹脂材のめっき被処理面にめっきにより導体層を形成する導体層形成工程」とを含むことが好ましい。 Next, the plating method according to the present invention includes, as the plating treatment, "sensitizing in which a solution containing stannous chloride as a main component is brought into contact with the surface of the resin material for 30 seconds to 3 minutes to adsorb tin ions. treatment step” and “after the sensitizing treatment step, a solution containing palladium chloride as a main component is brought into contact with the surface of the resin material to be plated for 30 seconds to 3 minutes to deposit palladium. and a "conductor layer forming step of forming a conductor layer on the surface of the resin material to be plated by plating after the activating treatment step".
本発明に係るめっき方法では、上述したセンシタイジング処理工程とアクティベーティング処理工程とをこの順番で行うことにより、紫外線照射面の触媒吸着量が多くなり、紫外線非照射面に対する活性度の差により導体層形成工程で選択的なめっき析出が可能となる。なお、本発明に係るめっき方法において、センシタイジング処理工程とアクティベーティング処理工程とは、繰り返して複数回行うこともできる。以下に、本発明のめっき処理である、センシタイジング処理工程、アクティベーティング処理工程、及び導体層形成工程について説明する。 In the plating method according to the present invention, the above-described sensitizing treatment step and activating treatment step are performed in this order, so that the catalyst adsorption amount on the ultraviolet irradiation surface increases, and the difference in activity with respect to the ultraviolet non-irradiation surface. Selective plating deposition becomes possible in the conductor layer forming process. In addition, in the plating method according to the present invention, the sensitizing treatment step and the activating treatment step can be repeated multiple times. The sensitizing treatment step, the activating treatment step, and the conductor layer forming step, which are the plating treatments of the present invention, will be described below.
Ａ－２．めっき処理
以下、センシタイジング処理工程とアクティベーティング処理工程と導体層形成工程とに分けて説明する。
A-2. Plating Treatment Hereinafter, the description will be divided into a sensitizing treatment step, an activating treatment step, and a conductor layer forming step.
＜センシタイジング処理工程について＞
本発明のセンシタイジング（感受性化）処理工程では、樹脂材の表面に対して、塩化第一スズを主成分として含む溶液を３０秒間～３分間接触させてスズイオン（Ｓｎ２＋）を吸着させる。上述した脱脂工程の後にこの条件で樹脂材のめっき被処理面に還元力の強いスズイオンを吸着させることで、後のアクティベーティング処理工程で活性なパラジウム触媒核を当該めっき被処理面に吸着させることができ、当該めっき被処理面の表面に導体層を均一に形成することが可能となる。なお、このような効果を安定的に得るには、当該溶液中のスズ濃度は、１～１００ｍｍｏｌ／Ｌであることが好ましい。ここで、樹脂材の表面に塩化第一スズを主成分として含む溶液を接触させる時間が３０秒間未満の場合には、樹脂材のめっき被処理面にスズイオンを十分に吸着させることができないため、選択めっき性の向上を十分に図ることができない。一方、樹脂材の表面に塩化第一スズを主成分として含む溶液を接触させる時間が３分間を超える場合には、当該めっき被処理面の表面に導体層を均一に形成する効果が飽和してコストメリットがない。
<Regarding the Sensitizing Process>
In the sensitizing treatment step of the present invention, a solution containing stannous chloride as a main component is brought into contact with the surface of the resin material for 30 seconds to 3 minutes to adsorb tin ions (Sn 2+ ). After the degreasing process described above, tin ions having a strong reducing power are adsorbed on the surface of the resin material to be plated under these conditions, so that active palladium catalyst nuclei are adsorbed on the surface to be plated in the subsequent activation treatment step. It is possible to uniformly form a conductor layer on the surface of the plating process surface. In order to stably obtain such effects, the tin concentration in the solution is preferably 1 to 100 mmol/L. Here, when the solution containing stannous chloride as a main component is brought into contact with the surface of the resin material for less than 30 seconds, tin ions cannot be sufficiently adsorbed on the surface of the resin material to be plated. It is not possible to sufficiently improve selective plating properties. On the other hand, when the solution containing stannous chloride as a main component is brought into contact with the surface of the resin material for more than 3 minutes, the effect of uniformly forming a conductor layer on the surface to be plated is saturated. No cost advantage.
＜アクティベーティング処理工程について＞
本発明のアクティベーティング（触媒化）処理工程では、樹脂材の表面に対して、塩化パラジウムを主成分として含む溶液を３０秒間～３分間接触させてパラジウムイオン（Ｐｄ２＋）をパラジウム金属（Ｐｄ）として析出させる。上述したセンシタイジング処理工程の後にこの条件で樹脂材のめっき被処理面に触媒核となるパラジウムを析出（パラジウム活性化）させることで、後工程において無電解めっき反応を良好にすることができ、当該めっき被処理面に導体層を均一に形成することが可能となる。パラジウムは塩酸酸性で可溶のため、濃塩酸を０．１～１０ｍｌ／Ｌ添加する。なお、このような効果を安定的に得るには、当該溶液中のパラジウム濃度は、０．１～５ｍｍｏｌ／Ｌであることが好ましい。ここで、樹脂材の表面に塩化パラジウムを主成分として含む溶液を接触させる時間が３０秒間未満の場合には、樹脂材のめっき被処理面にパラジウムを十分に析出させることができないため、選択めっき性の向上を十分に図ることができない。一方、樹脂材の表面に塩化パラジウムを主成分として含む溶液を接触させる時間が３分間を超える場合には、当該めっき被処理面の表面に導体層を均一に形成する効果が飽和してコストメリットがない。
<Regarding the activation process>
In the activating (catalyzing) treatment step of the present invention, a solution containing palladium chloride as a main component is brought into contact with the surface of the resin material for 30 seconds to 3 minutes to transform palladium ions (Pd 2+ ) into palladium metal (Pd ). After the above-mentioned sensitizing treatment process, by depositing palladium as a catalyst core on the surface of the resin material to be plated under these conditions (activating palladium), the electroless plating reaction in the subsequent process can be improved. , it becomes possible to uniformly form a conductor layer on the surface to be plated. Since palladium is soluble in hydrochloric acid, 0.1 to 10 ml/L of concentrated hydrochloric acid is added. In order to stably obtain such effects, the palladium concentration in the solution is preferably 0.1 to 5 mmol/L. Here, when the solution containing palladium chloride as a main component is brought into contact with the surface of the resin material for less than 30 seconds, palladium cannot be sufficiently deposited on the surface of the resin material to be plated, so selective plating is required. It is not possible to sufficiently improve the performance. On the other hand, when the solution containing palladium chloride as the main component is brought into contact with the surface of the resin material for more than 3 minutes, the effect of uniformly forming a conductor layer on the surface to be plated is saturated, resulting in cost savings. There is no
なお、本発明に係るめっき方法では、上述したアクティベーティング処理工程と後述する導体層形成工程との間で、樹脂材の紫外線照射していない部分に吸着したパラジウムを除去する脱パラジウム工程を含むことも好ましい。本脱パラジウム工程を採用することで、選択めっき性の更なる向上を図ることができる。ここで、パラジウムを除去する方法は特に限定されるものではなく、例えばクエン酸三ナトリウム溶液や市販のパラジウム除去剤等を含有する水溶液に当該樹脂材を浸漬する方法を採用することができる。 In addition, the plating method according to the present invention includes a depalladium removal step of removing palladium adsorbed on a portion of the resin material not irradiated with ultraviolet rays, between the above-described activating treatment step and the below-described conductor layer forming step. is also preferred. By adopting this depalladium removal step, selective plating properties can be further improved. Here, the method for removing palladium is not particularly limited, and for example, a method of immersing the resin material in an aqueous solution containing a trisodium citrate solution or a commercially available palladium remover can be employed.
上述したセンシタイジング処理工程、及びアクティベーティング処理工程は、樹脂材等の不導体素地への触媒付与方法の一つとして知られており、スズイオンの還元力を利用した「センシタイザー－アクティベーター法（ｓｅｎｓｉｔｉｚｅｒ－ａｃｔｉｖａｔｏｒ ｐｒｏｃｅｓｓ）」で経る工程である。本発明では、めっき処理として、このセンシタイザー－アクティベーター法を採用することで、後の導体層形成工程で安定的に均一な導体層を形成することが可能となる。 The above-described sensitizing treatment process and activating treatment process are known as one of the methods of imparting a catalyst to a non-conductor substrate such as a resin material, and are known as the "sensitizer-activator method" that utilizes the reducing power of tin ions. (sensitizer-activator process)”. In the present invention, by adopting this sensitizer-activator method as the plating treatment, it becomes possible to stably form a uniform conductor layer in the subsequent conductor layer forming process.
また、以上ではパラジウム活性化方法として、センシタイザー－アクティベーター法を示したが、本発明に係るめっき方法はこの方法に限定されない。センシタイザー－アクティベーター法はセンシタイザー処理とアクティベーター処理とが別々の処理液を用いる所謂二液型処理であるが、本発明に係るめっき方法では、１つの処理液を用いてパラジウム活性化を行う所謂１液型処理を採用することもできる。１液型処理では、例えば、塩酸酸性水溶液中に塩化パラジウムと塩化スズとを含む溶液、また、酸性が弱い食塩タイプの水溶液に塩化パラジウムと塩化スズとを含む溶液、パラジウム錯体を含有する水溶液等の処理液を用いることができる。また、その後必要に応じて余分なスズを取り除く促進処理を行うこともできる。 In the above description, the sensitizer-activator method is shown as a method for activating palladium, but the plating method according to the present invention is not limited to this method. The sensitizer-activator method is a so-called two-liquid type treatment in which separate treatment solutions are used for the sensitizer treatment and the activator treatment. A one-component process can also be employed. In the one-liquid treatment, for example, a solution containing palladium chloride and tin chloride in an acidic aqueous solution of hydrochloric acid, a solution containing palladium chloride and tin chloride in a weakly acidic salt-type aqueous solution, an aqueous solution containing a palladium complex, etc. can be used. Moreover, after that, if necessary, an acceleration treatment for removing excess tin can be performed.
＜導体層形成工程について＞
本発明の導体層形成工程は、上述したアクティベーティング処理工程の後、樹脂材のめっき被処理面に導体層を形成するものである。当該導体層形成工程で形成される導体層は、センシタイザー－アクティベーター法を経ることで、めっき被処理面をナノメートルオーダーの微細構造に維持しつつ、当該めっき被処理面に対する当該導体層の密着性を高めることができる。従って、本発明の導体層形成工程で形成される導体層は、高周波信号を遅延なく安定的に伝送させることができ、電子機器に用いた場合に電気的特性のさらなる向上を図ることができるようになる。なお、この導体層形成工程では、導体層を形成する方法として、電解めっき処理及び無電解めっき処理のいずれを用いてもよい。また、これらめっき処理の条件は特に限定されるものではなく、公知の条件を適宜採用することができる。従って、当該めっき処理で用いるめっき浴には、任意の添加剤（クエン酸等の錯化剤や鉛またはビスマス等の安定剤等）を添加することも可能である。
<Regarding the conductor layer forming process>
In the conductor layer forming step of the present invention, a conductor layer is formed on the plated surface of the resin material after the above-described activating treatment step. The conductor layer formed in the conductor layer forming process is subjected to the sensitizer-activator method, thereby maintaining the fine structure of the surface to be plated in nanometer order, while maintaining the adhesion of the conductor layer to the surface to be plated. can enhance sexuality. Therefore, the conductor layer formed in the conductor layer forming step of the present invention can stably transmit high-frequency signals without delay, and can further improve electrical characteristics when used in electronic devices. become. In this conductor layer forming step, either electrolytic plating or electroless plating may be used as a method for forming the conductor layer. Moreover, the conditions for these plating treatments are not particularly limited, and known conditions can be appropriately employed. Therefore, arbitrary additives (complexing agents such as citric acid, stabilizers such as lead or bismuth, etc.) can be added to the plating bath used in the plating process.
上述のめっき処理で用いるめっき浴の浴温は、特に限定されないが、５０℃～８０℃であることが好ましい。めっき浴の浴温がこの条件を満たす場合には、このめっき浴に触媒付与された樹脂材が浸漬されたときに、当該樹脂材の表面にめっきが安定的に析出される。ここで、当該めっき浴の浴温が５０℃未満の場合には、めっきの析出速度が低下する場合があるため好ましくない。一方、当該めっき浴の浴温が８０℃を超える場合には、形成しためっき被膜に膨れ、割れ、剥離等の不良が生じるおそれがあるため好ましくない。 Although the bath temperature of the plating bath used in the above-described plating treatment is not particularly limited, it is preferably 50°C to 80°C. When the bath temperature of the plating bath satisfies this condition, plating is stably deposited on the surface of the resin material to which a catalyst has been added when the resin material is immersed in the plating bath. Here, if the bath temperature of the plating bath is less than 50° C., the deposition rate of plating may decrease, which is not preferable. On the other hand, when the bath temperature of the plating bath exceeds 80° C., defects such as blistering, cracking, and peeling may occur in the formed plating film, which is not preferable.
また、本発明の導体層形成工程は、樹脂材のめっき被処理面に厚さ０．１～５μｍのニッケル－リン層を形成した後に、当該ニッケル－リン層の表面に厚さ１０～３５μｍの銅層を形成することが好ましい。ニッケル－リン層は、めっき処理によって樹脂材のめっき被処理面の形状に影響されずに均一な厚みに形成することができ、また、樹脂材との密着力をより強固なものとすることができる。従って、本発明の導体層は、このような層構成とすることで、樹脂材と導体層との界面における接合強度を維持しつつ、高周波信号の伝送損失を小さく抑えることができる。 Further, in the conductor layer forming step of the present invention, after forming a nickel-phosphorus layer with a thickness of 0.1 to 5 μm on the surface to be plated of the resin material, the nickel-phosphorus layer has a thickness of 10 to 35 μm on the surface of the nickel-phosphorus layer. Forming a copper layer is preferred. The nickel-phosphorus layer can be formed with a uniform thickness by plating without being affected by the shape of the surface of the resin material to be plated, and the adhesion to the resin material can be strengthened. can. Therefore, the conductor layer of the present invention having such a layer structure can maintain the bonding strength at the interface between the resin material and the conductor layer while suppressing the transmission loss of high-frequency signals.
ここで、上述したニッケル－リン層の厚さが０．１μｍ未満の場合には、導体層の強度低下を招くと共に、当該ニッケル－リン層の被覆が不十分となり、樹脂材に対するアンカー効果を十分に得ることができない。一方、上述したニッケル－リン層の厚さが５μｍを超える場合には、当該ニッケル被膜の形成に時間がかかり、コストメリットがない。 Here, if the thickness of the nickel-phosphorus layer described above is less than 0.1 μm, the strength of the conductor layer is lowered, and the coverage of the nickel-phosphorus layer becomes insufficient, resulting in a sufficient anchor effect for the resin material. can't get to On the other hand, if the thickness of the nickel-phosphorus layer exceeds 5 μm, it takes a long time to form the nickel coating, and there is no cost advantage.
また、上述した銅層の厚さが１０μｍ未満の場合には、上述したニッケル－リン層との接合強度を向上させる効果を十分に得ることができない。一方、上述した銅層の厚さが３５μｍを超える場合には、当該銅層の形成に時間がかかり、コストメリットがない。 Further, when the thickness of the copper layer is less than 10 μm, the effect of improving the bonding strength with the nickel-phosphorus layer cannot be sufficiently obtained. On the other hand, if the thickness of the copper layer exceeds 35 μm, it takes time to form the copper layer, and there is no cost advantage.
Ｂ．本発明に係る配線板
本発明に係る配線板は、上述した本発明に係るめっき方法を用いて得られることを特徴とする。ゆえに、本発明に係る配線板は、配線（導体層）が微細化しても当該配線と配線基材との密着性に優れたものとなる。また、本発明に係る配線板は、配線の表面粗度が低く抑えられたものとなり、表皮効果による信号の遅延が抑制されるため、高周波回路用として好適である。
B. Wiring Board According to the Present Invention A wiring board according to the present invention is obtained by using the above-described plating method according to the present invention. Therefore, the wiring board according to the present invention has excellent adhesion between the wiring (conductor layer) and the wiring substrate even when the wiring (conductor layer) is miniaturized. Moreover, the wiring board according to the present invention is suitable for high-frequency circuits because the surface roughness of the wiring is suppressed to a low level, and signal delay due to the skin effect is suppressed.
以上に、本発明に係るめっき方法、及びそれを用いた配線板に関して説明したが、以下に本発明の実施例を示し、本発明をより詳細に説明する。なお、本発明はこれらの例により何ら限定されるものではない。 The plating method according to the present invention and the wiring board using the same have been explained above. In addition, the present invention is not limited at all by these examples.
本実施例１では、試験体として、５０ｍｍ×５０ｍｍ×厚さ５ｍｍの大きさで、算術平均高さＳａが５００ｎｍのＬＣＰ基板を樹脂材として用意した。そして、当該樹脂材の表面に幅１０ｍｍで長さ５０ｍｍの矩形状の導体層をめっきにより形成した。具体的には、図１のフローチャートに示す如く、紫外線照射工程（ステップＳ１０）、アルカリ脱脂工程（ステップＳ２０）、センシタイジング処理工程（ステップＳ３０）、アクティベーティング処理工程（ステップＳ４０）、脱パラジウム工程（ステップＳ５０）、無電解ニッケル－リンめっき処理工程（ステップＳ６０）、無電解銅めっき処理工程（ステップＳ７０）を順に行い、当該樹脂材の表面に導体層を形成した。そして、このめっき方法を用いて形成された導体層（めっき被膜）について、めっきの選択性、めっき被膜表面の平滑性、及び樹脂材に対するめっき被膜の密着性の確認を行った。 In Example 1, an LCP substrate having a size of 50 mm×50 mm×5 mm in thickness and an arithmetic mean height Sa of 500 nm was prepared as a resin material as a test piece. A rectangular conductor layer having a width of 10 mm and a length of 50 mm was formed on the surface of the resin material by plating. Specifically, as shown in the flowchart of FIG. 1, an ultraviolet irradiation step (step S10), an alkaline degreasing step (step S20), a sensitizing treatment step (step S30), an activating treatment step (step S40), A palladium step (step S50), an electroless nickel-phosphorus plating step (step S60), and an electroless copper plating step (step S70) were sequentially performed to form a conductor layer on the surface of the resin material. Then, the selectivity of plating, the smoothness of the surface of the plated film, and the adhesion of the plated film to the resin material were confirmed for the conductor layer (plated film) formed using this plating method.
本実施例１では、めっき前処理として、紫外線照射工程、及びアルカリ脱脂工程を実施した。紫外線照射工程では、この樹脂材のめっき被処理面に対してＫｒＦレーザーにより紫外線を照射した。このとき、紫外線照射工程の直前と直後における、めっき被処理面の算術平均高さＳａの差は１２ｎｍであった。その後、アルカリ脱脂工程では、当該樹脂材を、４０℃の水酸化ナトリウム溶液（日本カニゼン株式会社製「品番：Ｋ－３５０」）に５分間浸漬させてアルカリ脱脂を行った。このとき、脱脂工程の直前と直後における、めっき被処理面の算術平均高さＳａの差は５ｎｍであった。 In Example 1, an ultraviolet irradiation step and an alkali degreasing step were carried out as pretreatments for plating. In the ultraviolet irradiation step, the surface of the resin material to be plated was irradiated with ultraviolet rays using a KrF laser. At this time, the difference in the arithmetic mean height Sa of the surface to be plated immediately before and after the ultraviolet irradiation step was 12 nm. After that, in the alkaline degreasing step, the resin material was immersed in a 40° C. sodium hydroxide solution ("product number: K-350" manufactured by Nippon Kanigen Co., Ltd.) for 5 minutes to perform alkaline degreasing. At this time, the difference in the arithmetic mean height Sa of the surface to be plated immediately before and after the degreasing step was 5 nm.
次いで、めっき処理として、センシタイジング処理工程、アクティベーティング処理工程、脱パラジウム工程、無電解ニッケル－リンめっき処理工程、及び無電解銅めっき処理工程を実施した。センシタイジング処理工程では、試験体となる樹脂材を、塩化第一スズを主成分として含む溶液（日本カニゼン株式会社製「品名：ピンクシューマー」）に３分間浸漬した。その後、アクティベーティング処理工程では、当該樹脂材を、塩化パラジウムを主成分として含む溶液（日本カニゼン株式会社製「品名：レッドシューマー」）を通常の４分の１に希釈した溶液に３分間浸漬して、めっき被処理面に対して触媒を吸着させた。その後、脱パラジウム工程では、当該樹脂材を、クエン酸三ナトリウム溶液（２０ｇ／Ｌ）に５分間攪拌（３００ｒｐｍ）させながら浸漬した。その後、無電解ニッケル－リンめっき処理工程では、当該めっき被処理面に対し、無電解ニッケルめっき液（日本カニゼン株式会社製「品番：シューマーＳＫ１０１」）（温度：７０℃、ｐＨ：１０）を用いて１５分間のめっき処理を施した。その後、無電解銅めっき処理工程では、当該無電解ニッケル－リンめっき処理工程を行った後直ぐに無電解銅めっき液（奥野製薬工業社製「ＯＰＣカッパーＭＩＣ－ＢＬ」）（温度：７０℃、ｐＨ：１０）を用いて１５分間のめっき処理を施した。 Next, as plating treatments, a sensitizing treatment step, an activating treatment step, a depalladium removal step, an electroless nickel-phosphorus plating treatment step, and an electroless copper plating treatment step were carried out. In the sensitizing treatment step, the resin material to be the specimen was immersed for 3 minutes in a solution containing stannous chloride as a main component (manufactured by Nippon Kanigen Co., Ltd., product name: Pink Schumer). After that, in the activating treatment step, the resin material is immersed in a solution containing palladium chloride as a main component ("product name: Red Sumer" manufactured by Nippon Kanigen Co., Ltd.) diluted to 1/4 of the usual solution for 3 minutes. Then, the catalyst was adsorbed on the surface to be plated. Thereafter, in the depalladium removal step, the resin material was immersed in a trisodium citrate solution (20 g/L) with stirring (300 rpm) for 5 minutes. After that, in the electroless nickel-phosphorus plating treatment process, an electroless nickel plating solution (manufactured by Nippon Kanigen Co., Ltd. "Product number: Schumer SK101") (temperature: 70 ° C., pH: 10) is used on the surface to be plated. was plated for 15 minutes. After that, in the electroless copper plating treatment step, immediately after the electroless nickel-phosphorus plating treatment step, the electroless copper plating solution ("OPC Copper MIC-BL" manufactured by Okuno Chemical Industry Co., Ltd.) (temperature: 70 ° C., pH : 10) for 15 minutes.
実施例１では、上述した各工程を経て得られためっき被膜について、選択めっき性を評価した。具体的に、選択めっき性の評価では、めっき被処理面における所定の箇所にめっきが正確に析出しているかを電子顕微鏡（倍率１００倍）により確認した。ここで、選択めっき性の評価は、紫外線照射部には完全に無電解ニッケル－リンめっき被膜が形成され、且つ紫外線未照射部には全くめっき析出がみられない場合を「〇」とし、紫外線照射部に少しでもめっき未析出がみられる場合、又は紫外線未照射部に少しでもめっき析出がみられた場合を「△」とし、紫外線照射部においてめっき未析出が顕著な場合、又は紫外線未照射部においてめっき析出が顕著な場合を「×」とした。 In Example 1, the selective plating property was evaluated for the plating film obtained through each of the steps described above. Specifically, in the selective plating property evaluation, it was confirmed by an electron microscope (magnification: 100) whether the plating was accurately deposited on the predetermined portions of the surface to be plated. Here, in the evaluation of selective plating, the case where an electroless nickel-phosphorus plating film is completely formed in the ultraviolet irradiation part and no plating deposition is observed in the ultraviolet irradiation unirradiated part is evaluated as "○", and the ultraviolet light If there is even a small amount of undeposited plating in the irradiated area, or if even a small amount of plating is observed in the area that has not been irradiated with UV rays, the case is marked as "△". The case where the plating deposition was remarkable in the part was set as "x".
また、実施例１では、上述した各工程を経て得られためっき被膜において、めっき被膜表面の平滑性を評価した。めっき被膜表面の平滑性の評価は、算術平均高さＳａで評価した。このとき、算術平均高さＳａは、レーザー顕微鏡「株式会社キーエンス製 ＶＫ－Ｘ型」を使用して測定した。当該めっき被膜の表面粗さは、１ＧＨｚ帯の高周波信号を伝送することを想定して、算術平均高さＳａが６００ｎｍ未満を「〇」とし、算術平均高さＳａが６００ｎｍ以上で且つ１０００ｎｍ未満の場合を「△」とし、算術平均高さＳａが１０００ｎｍ以上の場合を「×」とした。参考までに、実施例１におけるめっき被膜の表面粗さは、算術平均高さＳａの平均値で約５５０ｎｍであった。 Moreover, in Example 1, the smoothness of the plating film surface was evaluated in the plating film obtained through each of the steps described above. The smoothness of the plated film surface was evaluated by arithmetic mean height Sa. At this time, the arithmetic mean height Sa was measured using a laser microscope "VK-X type manufactured by Keyence Corporation". Regarding the surface roughness of the plating film, assuming that a high-frequency signal in the 1 GHz band is transmitted, the arithmetic mean height Sa of less than 600 nm is “O”, and the arithmetic mean height Sa is 600 nm or more and less than 1000 nm. The cases where the arithmetic mean height Sa was 1000 nm or more were evaluated as "x". For reference, the surface roughness of the plating film in Example 1 was about 550 nm in terms of the average arithmetic mean height Sa.
さらに、実施例１では、上述した各工程を経て得られためっき被膜の密着性を、スタッドプル（ｓｔｕｄ ｐｕｌｌ）と称される試験方法で評価した。具体的には、樹脂材表面に形成しためっき被膜の表面にアルミニウム製のスタッドピン（直径７．１ｍｍ）を接着剤を用いて接合し、当該樹脂材を支えた上で当該スタッドピンに垂直引張荷重（１．０ｋｇ／ｓ）を加えていき、破断点での荷重（ｋｇ／ｃｍ２）を測定した。 Furthermore, in Example 1, the adhesion of the plating film obtained through each of the steps described above was evaluated by a test method called stud pull. Specifically, an aluminum stud pin (diameter 7.1 mm) is bonded to the surface of the plating film formed on the resin material surface using an adhesive, and the resin material is supported and perpendicularly pulled to the stud pin. A load (1.0 kg/s) was applied and the load (kg/cm 2 ) at the breaking point was measured.
以下に示す表１には、上述した条件で選択めっき性、めっき平滑性、及びめっき密着力について確認を行った結果を示す。表１には、実施例１以外にも、実施例２，３、比較例１～３の結果を併せて示す。 Table 1 shown below shows the results of confirming selective plating properties, plating smoothness, and plating adhesion under the conditions described above. Table 1 also shows the results of Examples 2 and 3 and Comparative Examples 1 to 3 in addition to Example 1.
実施例２では、実施例１と同様に、めっきの選択性、めっき被膜表面の平滑性、及び樹脂材に対するめっき被膜の密着性の確認を行った。実施例２では、試験体として実施例１と同じ樹脂材を用意した。また、実施例２では、実施例１と同様に図１のフローチャートに示す工程を行い、当該樹脂材の表面に導体層を形成した。 In Example 2, as in Example 1, the selectivity of plating, the smoothness of the surface of the plating film, and the adhesion of the plating film to the resin material were confirmed. In Example 2, the same resin material as in Example 1 was prepared as a specimen. In Example 2, the steps shown in the flowchart of FIG. 1 were performed in the same manner as in Example 1 to form a conductor layer on the surface of the resin material.
実施例２において実施例１と異なる条件は、紫外線照射工程で紫外線照射工程の直前と直後におけるめっき被処理面の算術平均高さＳａの差が５８ｎｍである点、アルカリ脱脂工程で２５℃の水酸化ナトリウム溶液に浸漬させ、脱脂工程の直前と直後におけるめっき被処理面の算術平均高さＳａの差が３ｎｍである点、センシタイジング処理工程及びアクティベーティング処理工程で樹脂材を浸漬させる時間が１分間である点である。図１のフローチャートに示す各工程に関する詳細は、既に実施例１で説明しているため、ここでは省略する。 Example 2 differs from Example 1 in that the difference in the arithmetic mean height Sa of the plated surface immediately before and after the ultraviolet irradiation step is 58 nm in the ultraviolet irradiation step, The difference in the arithmetic mean height Sa of the surface to be plated immediately before and after the degreasing step when immersed in the sodium oxide solution is 3 nm, and the length of time the resin material is immersed in the sensitizing treatment step and the activating treatment step. is one minute. Since the details of each step shown in the flowchart of FIG. 1 have already been described in the first embodiment, they are omitted here.
表１には、上述した条件で選択めっき性、めっき平滑性、及びめっき密着力について確認を行った結果を示す。参考までに、実施例２におけるめっき被膜の表面粗さは、算術平均高さＳａの平均値で約５９０ｎｍであった。ここで、これらの確認を行うに際して、実施例１と同じ方法を採用した。そのため、これら方法に関する説明は省略する。 Table 1 shows the results of confirmation of selective plating properties, plating smoothness, and plating adhesion under the conditions described above. For reference, the surface roughness of the plating film in Example 2 was approximately 590 nm in terms of the average arithmetic mean height Sa. Here, the same method as in Example 1 was employed for these confirmations. Therefore, descriptions of these methods are omitted.
実施例３では、実施例１と同様に、めっきの選択性、めっき被膜表面の平滑性、及び樹脂材に対するめっき被膜の密着性の確認を行った。実施例３では、試験体として実施例１と同じ樹脂材を用意した。また、実施例３では、実施例１と同様に図１のフローチャートに示す工程を行い、当該樹脂材の表面に導体層を形成した。 In Example 3, as in Example 1, the selectivity of plating, the smoothness of the surface of the plating film, and the adhesion of the plating film to the resin material were confirmed. In Example 3, the same resin material as in Example 1 was prepared as a specimen. In Example 3, the steps shown in the flowchart of FIG. 1 were performed in the same manner as in Example 1 to form a conductor layer on the surface of the resin material.
実施例３において、実施例１と異なる条件は、紫外線照射工程で紫外線照射工程の直前と直後におけるめっき被処理面の算術平均高さＳａの差が６ｎｍである点、アルカリ脱脂工程で２５℃の水酸化ナトリウム溶液に浸漬させ、脱脂工程の直前と直後におけるめっき被処理面の算術平均高さＳａの差が３ｎｍである点、センシタイジング処理工程及びアクティベーティング処理工程で樹脂材を浸漬させる時間が３０秒間である点、無電解ニッケル－リンめっき処理工程及び無電解銅めっき処理工程でめっき浴の温度が６０℃である点である。図１のフローチャートに示す各工程に関する詳細は、既に実施例１で説明しているため、ここでは省略する。 In Example 3, the conditions different from Example 1 were that in the ultraviolet irradiation step, the difference in the arithmetic mean height Sa of the plated surface immediately before and after the ultraviolet irradiation step was 6 nm, and in the alkali degreasing step, the temperature was reduced to 25°C. Immersed in a sodium hydroxide solution, the difference in arithmetic mean height Sa of the plated surface immediately before and after the degreasing process is 3 nm, and the resin material is immersed in the sensitizing treatment process and the activating treatment process. The time is 30 seconds, and the temperature of the plating bath is 60° C. in the electroless nickel-phosphorus plating process and the electroless copper plating process. Since the details of each step shown in the flowchart of FIG. 1 have already been described in the first embodiment, they are omitted here.
表１には、上述した条件で選択めっき性、めっき平滑性、及びめっき密着力について確認を行った結果を示す。参考までに、実施例３におけるめっき被膜の表面粗さは、算術平均高さＳａの平均値で約５３０ｎｍであった。ここで、これらの確認を行うに際して、実施例１と同じ方法を採用した。そのため、これら方法に関する説明は省略する。 Table 1 shows the results of confirmation of selective plating properties, plating smoothness, and plating adhesion under the conditions described above. For reference, the surface roughness of the plating film in Example 3 was approximately 530 nm in terms of the average arithmetic mean height Sa. Here, the same method as in Example 1 was employed for these confirmations. Therefore, descriptions of these methods are omitted.
［比較例１］
比較例１では、実施例１と同様に、めっきの選択性、めっき被膜表面の平滑性、及び樹脂材に対するめっき被膜の密着性の確認を行った。比較例１では、試験体として実施例１と同じ樹脂材を用意した。また、比較例１では、実施例１と同様に図１のフローチャートに示す工程を行い、当該樹脂材の表面に導体層を形成した。
[Comparative Example 1]
In Comparative Example 1, as in Example 1, the selectivity of plating, the smoothness of the surface of the plating film, and the adhesion of the plating film to the resin material were confirmed. In Comparative Example 1, the same resin material as in Example 1 was prepared as a specimen. In Comparative Example 1, the steps shown in the flowchart of FIG. 1 were performed in the same manner as in Example 1 to form a conductor layer on the surface of the resin material.
比較例１において、実施例１と異なる条件は、紫外線照射工程で紫外線照射工程の直前と直後におけるめっき被処理面の算術平均高さＳａの差が１０４３ｎｍである点、アルカリ脱脂工程で２５℃の水酸化ナトリウム溶液に浸漬させ、脱脂工程の直前と直後におけるめっき被処理面の算術平均高さＳａの差が３ｎｍである点、センシタイジング処理工程及びアクティベーティング処理工程で樹脂材を浸漬させる時間が４５秒間である点、無電解ニッケル－リンめっき処理工程及び無電解銅めっき処理工程でめっき浴の温度が６０℃である点である。図１のフローチャートに示す各工程に関する詳細は、既に実施例１で説明しているため、ここでは省略する。 In Comparative Example 1, the conditions different from those in Example 1 were that the difference in the arithmetic mean height Sa of the plated surface immediately before and after the ultraviolet irradiation step was 1043 nm in the ultraviolet irradiation step, and that the alkaline degreasing step was performed at 25°C. Immersed in a sodium hydroxide solution, the difference in arithmetic mean height Sa of the plated surface immediately before and after the degreasing process is 3 nm, and the resin material is immersed in the sensitizing treatment process and the activating treatment process. The time is 45 seconds, and the temperature of the plating bath is 60° C. in the electroless nickel-phosphorus plating process and the electroless copper plating process. Since the details of each step shown in the flowchart of FIG. 1 have already been described in the first embodiment, they are omitted here.
表１には、上述した条件で選択めっき性、めっき平滑性、及びめっき密着力について確認を行った結果を示す。参考までに、比較例１におけるめっき被膜の表面粗さは、算術平均高さＳａの平均値で約１６００ｎｍであった。ここで、これらの確認を行うに際して、実施例１と同じ方法を採用した。そのため、これら方法に関する説明は省略する。 Table 1 shows the results of confirmation of selective plating properties, plating smoothness, and plating adhesion under the conditions described above. For reference, the surface roughness of the plating film in Comparative Example 1 was about 1600 nm in terms of the average arithmetic mean height Sa. Here, the same method as in Example 1 was employed for these confirmations. Therefore, descriptions of these methods are omitted.
［比較例２］
比較例２では、実施例１と同様に、めっきの選択性、めっき被膜表面の平滑性、及び樹脂材に対するめっき被膜の密着性の確認を行った。比較例２では、試験体として実施例１と同じ樹脂材を用意した。また、比較例２では、紫外線照射工程を行っていない点を除き、実施例１と同様に図１のフローチャートに示す工程を行い、当該樹脂材の表面に導体層を形成した。
[Comparative Example 2]
In Comparative Example 2, as in Example 1, the selectivity of plating, the smoothness of the surface of the plating film, and the adhesion of the plating film to the resin material were confirmed. In Comparative Example 2, the same resin material as in Example 1 was prepared as a specimen. In Comparative Example 2, the process shown in the flowchart of FIG. 1 was performed in the same manner as in Example 1, except that the ultraviolet irradiation process was not performed, to form a conductor layer on the surface of the resin material.
比較例２において、紫外線照射工程を行っていないことの他、実施例１と異なる条件は、アルカリ脱脂工程で２５℃の水酸化ナトリウム溶液に浸漬させ、脱脂工程の直前と直後におけるめっき被処理面の算術平均高さＳａの差が１ｎｍである点、センシタイジング処理工程及びアクティベーティング処理工程で樹脂材を浸漬させる時間が１分間である点、無電解ニッケル－リンめっき処理工程及び無電解銅めっき処理工程でめっき浴の温度が６０℃である点である。図１のフローチャートに示す各工程に関する詳細は、既に実施例１で説明しているため、ここでは省略する。 In Comparative Example 2, the conditions different from those in Example 1 were that the ultraviolet irradiation step was not performed and the surface to be plated was immersed in a sodium hydroxide solution at 25° C. in the alkaline degreasing step immediately before and after the degreasing step. The difference in the arithmetic mean height Sa is 1 nm, the time for immersing the resin material in the sensitizing treatment step and the activating treatment step is 1 minute, the electroless nickel-phosphorus plating treatment step and the electroless The point is that the temperature of the plating bath is 60° C. in the copper plating process. Since the details of each step shown in the flowchart of FIG. 1 have already been described in the first embodiment, they are omitted here.
表１には、上述した条件で選択めっき性、めっき平滑性、及びめっき密着力について確認を行った結果を示す。参考までに、比較例２におけるめっき被膜の表面粗さは、算術平均高さＳａの平均値で約６２０ｎｍであった。ここで、これらの確認を行うに際して、実施例１と同じ方法を採用した。そのため、これら方法に関する説明は省略する。 Table 1 shows the results of confirmation of selective plating properties, plating smoothness, and plating adhesion under the conditions described above. For reference, the surface roughness of the plating film in Comparative Example 2 was about 620 nm in terms of the average arithmetic mean height Sa. Here, the same method as in Example 1 was employed for these confirmations. Therefore, descriptions of these methods are omitted.
［比較例３］
比較例３では、実施例１と同様に、めっきの選択性、めっき被膜表面の平滑性、及び樹脂材に対するめっき被膜の密着性の確認を行った。比較例３では、試験体として実施例１と同じ樹脂材を用意した。また、比較例３では、紫外線照射工程及びアルカリ脱脂工程を行っていない点を除き、実施例１と同様に図１のフローチャートに示す工程を行い、当該樹脂材の表面に導体層を形成した。
[Comparative Example 3]
In Comparative Example 3, as in Example 1, the selectivity of plating, the smoothness of the surface of the plating film, and the adhesion of the plating film to the resin material were confirmed. In Comparative Example 3, the same resin material as in Example 1 was prepared as a specimen. In Comparative Example 3, the steps shown in the flowchart of FIG. 1 were performed in the same manner as in Example 1, except that the ultraviolet irradiation step and the alkali degreasing step were not performed, and a conductor layer was formed on the surface of the resin material.
比較例３において、紫外線照射工程及びアルカリ脱脂工程を行っていないことの他、実施例１と異なる条件は、センシタイジング処理工程及びアクティベーティング処理工程で樹脂材を浸漬させる時間が１分間である点、無電解ニッケル－リンめっき処理工程及び無電解銅めっき処理工程でめっき浴の温度が６０℃である点である。図１のフローチャートに示す各工程に関する詳細は、既に実施例１で説明しているため、ここでは省略する。 In Comparative Example 3, the ultraviolet irradiation step and the alkali degreasing step were not performed, and the conditions different from those in Example 1 were that the resin material was immersed for 1 minute in the sensitizing treatment step and the activating treatment step. One point is that the temperature of the plating bath is 60° C. in the electroless nickel-phosphorus plating process and the electroless copper plating process. Since the details of each step shown in the flowchart of FIG. 1 have already been described in the first embodiment, they are omitted here.
表１には、上述した条件で選択めっき性、めっき平滑性、及びめっき密着力について確認を行った結果を示す。参考までに、比較例３におけるめっき被膜の表面粗さは、算術平均高さＳａの平均値で約９００ｎｍであった。ここで、これらの確認を行うに際して、実施例１と同じ方法を採用した。そのため、これら方法に関する説明は省略する。 Table 1 shows the results of confirmation of selective plating properties, plating smoothness, and plating adhesion under the conditions described above. For reference, the surface roughness of the plating film in Comparative Example 3 was approximately 900 nm in terms of the average arithmetic mean height Sa. Here, the same method as in Example 1 was employed for these confirmations. Therefore, descriptions of these methods are omitted.
（結果及び評価）
表１より、樹脂材のめっき被処理面に対して、本発明の紫外線照射工程の条件「樹脂材の算術平均高さＳａが６０ｎｍ以下であるめっき被処理面に対して形状変形が生じない程度の紫外線を照射する」、及び本発明の脱脂工程の条件「樹脂材のめっき被処理面に対して２５～６０℃の脱脂剤を５分間～１０分間接触させて脱脂を行う」を満たすことで、選択めっき性、めっき平滑性、及びめっき密着性において総じて優れた結果が得られた。この結果より、これら条件を満たすことで、高周波信号の伝送速度の高速化を実現した導体層を樹脂材表面に形成できることが分かる。
(Results and evaluation)
From Table 1, for the surface to be plated of the resin material, the condition of the ultraviolet irradiation step of the present invention is "the extent to which shape deformation does not occur on the surface to be plated where the arithmetic mean height Sa of the resin material is 60 nm or less. and the condition of the degreasing process of the present invention, ``Degrease is performed by contacting the surface of the resin material to be plated with a degreasing agent at 25 to 60 ° C. for 5 to 10 minutes. , selective plating, plating smoothness, and plating adhesion were all excellent. From these results, it can be seen that by satisfying these conditions, a conductor layer that achieves high-speed transmission of high-frequency signals can be formed on the surface of the resin material.
また、紫外線照射工程の直前と直後におけるめっき被処理面の算術平均高さＳａの差の条件「１０ｎｍ～１０００ｎｍ」、及び脱脂工程の直前と直後におけるめっき被処理面の算術平均高さＳａの差の条件「３ｎｍ～１０ｎｍ」を満たす実施例１，２の試験体は、この条件を満たさない他の試験体に比べて選択めっき性及びめっき密着性に優れた結果が得られた。この結果より、さらにこれら条件を満たすことで、微細でありながら剥離や断線が生じ難い導体層を樹脂材表面に形成する効果が得られることが分かる。 In addition, the condition "10 nm to 1000 nm" for the difference in the arithmetic mean height Sa of the plated surface immediately before and after the ultraviolet irradiation step, and the difference in the arithmetic mean height Sa of the plated surface immediately before and after the degreasing step. The specimens of Examples 1 and 2 satisfying the condition "3 nm to 10 nm" in (1) showed better selective plating properties and plating adhesion than the other specimens which did not satisfy this condition. From this result, it can be seen that by satisfying these conditions, it is possible to obtain an effect of forming a fine conductor layer that is less likely to be peeled off or disconnected on the surface of the resin material.
本発明に係るめっき方法によれば、樹脂材と導体層との密着性を高めると共に、高周波回路用として好適な導体層を安定的に形成することができる。さらに、選択的に導体層を形成することが可能である。従って、本発明に係るめっき方法は、電子部品の小型軽量化、及び高性能化に対応することができ、加えて複雑な形状の樹脂材の表面に配線（立体配線）を精密に形成することができるという顕著な効果を奏する。また、本発明に係るめっき方法は、複雑な工程や装置を必要としないため、設備や処理のコストを抑え、安価な製品を提供するという点でも有利である。さらに、本発明は、有害物質である６価クロムを用いて樹脂材表面の粗化を行うエッチング処理工程が不要であるため、環境面でも好適である。 According to the plating method of the present invention, it is possible to improve the adhesion between the resin material and the conductor layer and stably form a conductor layer suitable for high-frequency circuits. Furthermore, it is possible to selectively form a conductor layer. Therefore, the plating method according to the present invention can cope with the reduction in size and weight of electronic parts and the improvement of their performance. It has a remarkable effect of being able to Moreover, since the plating method according to the present invention does not require complicated processes or equipment, it is advantageous in terms of reducing facility and processing costs and providing inexpensive products. In addition, the present invention does not require an etching process for roughening the surface of the resin material using hexavalent chromium, which is a hazardous substance, and is therefore environmentally friendly.
Ｓ１０…紫外線照射工程
Ｓ２０…アルカリ脱脂工程
Ｓ３０…センシタイジング処理工程
Ｓ４０…アクティベーティング処理工程
Ｓ５０…脱パラジウム工程
Ｓ６０…無電解ニッケル－リンめっき処理工程
Ｓ７０…無電解銅めっき処理工程
S10: UV irradiation step S20: Alkaline degreasing step S30: Sensitizing treatment step S40: Activating treatment step S50: Depalladium removal step S60: Electroless nickel-phosphorus plating treatment step S70: Electroless copper plating treatment step
Claims (8)
当該樹脂材のレーザー顕微鏡を用いた非接触式の測定による算術平均高さＳａが５００ｎｍ以下であるめっき被処理面に対して形状変形が生じない程度の紫外線を照射する紫外線照射工程と、
当該紫外線照射工程を行った後、当該樹脂材のめっき被処理面に対して２５～６０℃の脱脂剤を５分間～１０分間接触させて脱脂を行う脱脂工程とを含み、
その後、めっき処理を行い当該導体層を形成することを特徴とするめっき方法。 A plating method for forming a conductor layer only on a portion irradiated with ultraviolet rays on the surface of a resin material,
an ultraviolet irradiation step of irradiating a surface to be plated having an arithmetic mean height Sa of 500 nm or less as determined by non-contact measurement of the resin material using a laser microscope with ultraviolet rays to such an extent that shape deformation does not occur;
a degreasing step of contacting the surface of the resin material to be plated with a degreasing agent at 25 to 60° C. for 5 to 10 minutes after performing the ultraviolet irradiation step,
A plating method characterized by forming the conductor layer by performing plating thereafter.
当該センシタイジング処理工程の後、当該めっき被処理面に対して、塩化パラジウムを主成分として含む溶液を３０秒間～３分間接触させてパラジウムを析出させるアクティベーティング処理工程と、
当該アクティベーティング処理工程の後、当該めっき被処理面にめっきにより前記導体層を形成する導体層形成工程とを含む請求項１～請求項３のいずれかに記載のめっき方法。 The plating treatment includes a sensitizing treatment step in which a solution containing stannous chloride as a main component is brought into contact with the surface to be plated for 30 seconds to 3 minutes to adsorb tin ions;
After the sensitizing treatment step, an activating treatment step of depositing palladium by contacting the surface to be plated with a solution containing palladium chloride as a main component for 30 seconds to 3 minutes;
4. The plating method according to any one of claims 1 to 3, further comprising a conductor layer forming step of forming the conductor layer on the surface to be plated by plating after the activating treatment step.
当該ニッケル－リン層の表面に厚さ１０～３５μｍの銅層を形成する請求項４に記載のめっき方法。 In the conductor layer forming step, after forming a nickel-phosphorus layer having a thickness of 0.1 to 5 μm on the surface to be plated,
5. The plating method according to claim 4, wherein a copper layer having a thickness of 10 to 35 μm is formed on the surface of said nickel-phosphorus layer.
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