在不连续Pd粒子覆盖的非导体表面电沉积铜的研究

Early Stage Electrodeposition of Copper on Nonconductor ABS Covered with Noncontinuous Pd Particulates and Morphology of the Copper Coating

考察了在覆盖有分散Pd粒子的非导体表面电沉积铜的初始阶段,发现非导体在电沉积前的面电阻达到100MΩ/cm时可实现较快速度的电沉积。铜层生长前沿分为厚镀层区和薄镀层区两部分,厚镀层区外观为红色,形成致密的结晶;薄镀层区颜色发黑,小的铜晶粒在高能表面首先生成。离挂具点近的地方结晶致密,反之则结晶稀疏。SEM照片显示出最初沉积的铜层是以Pd为沉积点的不规则块状,其大小为2～5μm2,随后在众多连续状上有晶体缺陷的高能表面沉积出具有立方形状的铜晶体。电沉积铜过程的推动力是生长前沿高达106A/dm2的电流密度,先沉积的铜层起到挂具的作用直到非金属表面被完全覆盖。

The early stage electrodeposition of copper on nonconductor acrylonitrile butadiene styrene (ABS) covered with noncontinuous Pd clusters was investigated. The morphologies of the resulting copper coatings were observed using a scanning electron microscope. As the results, it was feasible to initiate relatively fast electrodeposition of copper on the surface of ABS when its electric resistance reached 100 MΩ/cm. The propagation front of the copper coating could be divided into two zones, i.e., the thick layer zone and the thin layer zone. The thick layer zone appeared to be red and was composed of compact copper crystallites, while the thin layer zone looked like black and contained dispersed copper particulates preferentially deposited at high-energy area. The copper crystallites near the contact strip were compact, while those away from the contact strip were incompact. In terms of the morphology, the initially electrodeposited copper coating had irregular block-like shape and was formed around the Pd particulates as the electrodeposition nuclei. The final cubic copper crystallites were formed with the successive electrodeposition of copper at the high-energy area of the continuous block-like deposits. The electric current density as high as 10 6 A/dm 2 at the propagation front acted as the driving force for the copper electrodeposition on nonconductor ABS, and the copper deposits formed in the early stage of plating could act as contact strip to help the completion of the electrodeposition of the nonconductor.