Deposition of Ni-Based Carbon Nanotube Composite Coatings By Using Laser Enhanced Electroless Plating

Abstract

Listen

Translate article

1 Introduction In recent years, the mask-less direct metal patterning on 3D shape plastic substrates has received considerable attention from the perspective of potential applications to such as 3D-molded interconnect device (3D-MID). 2-shot injection molding and Laser direct structuring (LDS) are the leading technology in this field. However, these technology are not direct metal patterning. In the case of LDS, The laser-activatable thermoplastic doped with a special additive was required for making a sensitized-activated surface by laser. When the thermoplastic was irradiation by laser beam, it was activated. A physical-chemical reaction forms metallic nuclei. These act as a catalyst for electroless plating. The metallization on activated pass was performed by electroless plating after laser-activation. Some recent researches have investigated the laser enhanced electroless plating and have reported that they could successfully and directly formed metal patterning on the plastic substrates by the laser enhanced electroless plating. The metallization on activated pass were performed by electroless plating after laser-activation. However, the effects of the laser wavelength and additives in plating bath is not clear. In this study, their effects on the laser enhanced electroless plating were investigated. Carbon nanotubes (CNTs) were used as additives for improving laser absorption. 2 Experimental Procedure Polyimide films as substrates were immersed in low phosphorus electroless nickel plating bath (Meltex, NI-426, 1-3% phosphorus). The polyimide films were not sensitized and were not activated. Laser beam irradiation performed on the substrates through quartz glass rods at room temperature. Laser wavelengths of 405nm, 532nm, 980nm were chosen. CNTs (Showa denko, VGCF-H, 0.4g/L) were added in the plating bath. 3. Results and discussion In the case of non-addition of CNTs, no nickel deposited on the polyimide film by laser irradiation of 405nm (0.15W), 532nm (1.5W), 980nm (6W) in wavelength. Non-deposition results from non-pretreatment, such as sensitizing and activating, and from the less laser absorption of substrates. In the case of addition of CNTs, Island-like nickel deposited on the polyimide films by using 980 nm Laser beam. The nickel deposits were nickel-based CNT composites. CNTs improved the absorption of Laser and led local heating on the substrates so that the composite coatings formed on the non-pretreated substrates. Figure 1