Sn-Nanorod-Supported Ag Nanoparticles as Efficient Catalysts for Electroless Deposition of Cu Conductive Tracks

Abstract

The applications of tin are extremely wide-ranging, in fields as diverse as Li-ion batteries, catalysis, and electronic packaging. It is always significant but still remains a great challenge to develop facile and efficient routes to synthesize Sn nanostructures. Herein, we report a facile chemical method to synthesize a Sn nanorod crystal at room temperature, and Ag ions are subsequently introduced to form the Sn-nanorod-supported Ag nanoparticles hybrid structure (Sn/Ag nanorods). The Sn/Ag nanorods exhibit comparable activity to the commercial Pd black in catalyzing the electroless copper deposition (ECD) reaction that is indispensable to fabricate printed circuit boards (PCBs). Furthermore, a screen printable adhesive is prepared by mixing the as-synthesized Sn/Ag nanorod powders and epoxy resin to fabricate activator patterns on epoxy laminate (EPL) and flexible substrates including polyethylene terephthalate (PET) and polytetrafluoroethylene (PTFE) fiber film. The printed areas are finally metalized by the ECD process to obtain the copper coatings with designed patterns that are confirmed to exhibit excellent electrical conductivity and flexibility.

Synthesis of Sn/Ag–Sn nanoparticles via room temperature galvanic reaction and diffusion

“…In a recent study of coating Ag onto Sn NRs, the as-synthesized Sn/Ag NRs consisted of only Sn NRs with Ag NPs dispersed on the surface of NRs and no intermetallic compound existed. 34 These observations are similar with our current study, however, the presence of a very thin layer of intermetallic compound between Sn NRs and Ag NPs was likely to have been overlooked in their study.…”

Laser-Induced Selective Metallization on Polymer Substrates Using Organocopper for Portable Electronics

“…11,12,27 Importantly, the selective surface activation is the necessary step for the selective electroless copper metallization. 17 During the ECP process, the copper ions (Cu 2+ ) in solution are gradually reduced by formaldehyde in the presence of catalytic sites. Subsequently, the redox reaction was carried out with the autocatalysis effect of copper.…”

“…In recent years, selective metallization on nonconductive polymer materials are extensively investigated because of their broad applications in the fields of integrated microelectronic and aesthetic decoration. − Generally, the main approaches for the fabrication of metalized patterns are photolithography, , ink printing, ,,,− screen printing, ligand-induced electroless plating (LIEP), , laser-assisted deposition, laser direct structuring (LDS), and so forth. Over the past decades, the photolithography technique has been a dominant industrially available method for surface patterning of substrates.…”

“…Then, the designed LDS materials performed the selective laser activation by the computer-controlled laser system to fabricate microrough structure and catalytic sites on the desired surface area, followed by electroless copper plating (ECP). In general, electroless plating is widely used in polymer metallization. ,, Importantly, the selective surface activation is the necessary step for the selective electroless copper metallization . During the ECP process, the copper ions (Cu 2+ ) in solution are gradually reduced by formaldehyde in the presence of catalytic sites.…”

PET Surface Modification with Inkjet-Printing Pd2+/Epoxy Resin Solution for Selective Electroless Copper Plating

“…Flexible electronics are able to maintain particular functions under bending or even folding, meeting the needs of miniaturization and portable electronic products. − Polyethylene terephthalate (PET) films with excellent flexibility and chemical stability have become one of the most popular substrates of flexible circuit boards. − Selective metallization on the PET surface forms copper circuits with good corrosion resistance and excellent electrical conductivity, which has attracted great attention. , Many strategies of selective metallization on the polymer surface have been studied, including electroplating, physical vapor deposition, laser surface alloying, and electroless plating. − Notably, the simple electroless plating process is capable of achieving mass production and is insensitive to the surface morphology of the substrate. Therefore, electroless plating has become a major method of polymer surface metallization. − The essential step of selective electroless plating conductive lines is to establish catalytic centers covering the target area on the surface of polymers. − However, the PET film with low surface energy and low roughness are not affinitive to the catalyst molecules or particles to form catalytic centers. − Thus, the surface treatment of PET is required.…”