Silver localization on polyimide using microcontact printing and electroless metallization

Silver localization is obtained on polyimide Kapton® HN (PI) in step by step processes combining surface treatments (chemical and plasma), microcontact printing (μCP) and electroless metal deposition. There processes are developed in order to obtain silver patterns onto flexible polymer surfaces at the micro and sub-micro scale. Patterns of silver dots or, at the opposite, of holes in silver layer, were obtained using the same PDMS polydimethylsiloxane (PDMS) stamp (positive/negative technology). Processes are based on the same first step, i.e. the PI surface functionalization with Ag(0) nanoparticles, catalyst to silver electroless metallization. μCP step is based on a localized passivation with self-assembled monolayers (SAMs) of octadecanethiol (CH3(CH2)17SH; ODT). Those molecules are locally printed either on a continuous silver deposit or on the Ag(0) catalytic nanoparticles. Then, chemical etching and/or electroless deposition complete the localization process. Geometry and dimensions of silver patterns are discussed, highlighting the main parameters influencing high resolution (sub-micrometric scale) of these silver patterns.