Electroless Plating Catalyst Performance of a Cationic Moiety Bearing Palladium Complex

Abstract

Conventionally, in the electroless plating of resin, surface modification has been necessary to generate carboxylate moieties that enhances palladium catalyst adsorption. To further enhance palladium adsorption, a variety of Pd(II) amino acid complexes were synthesized, which bear a cationic pendant group with affinity for the carboxylate generated on the resin, and performance as an electroless plating catalyst evaluated. The Pd(II) complexes were characterized using UV-vis spectroscopy, revealing chelation of the amine and carboxylate groups of amino acids to Pd(II). For the Pd(II) complexes of Arginine or Lysine, affinity of the cationic pendant groups to resin surface carboxylate groups was suggested by enhanced Pd adsorption, c.a. 80 fold increase compared to complexes without cationic moieties. Furthermore, even under mild surface modification conditions with 0.5 mol/dm 3 KOH, the Pd(II) complexed with Arginine or Lysine displayed performance as a electroless Ni catalyst, allowing for electolytic copper plated laminates of 1 kN/m adhesion strenghth.

Polyimide Metallization Using Nickel Nano-Film as both Catalyst and Barrier Layer of Copper Electroless Deposition

“…A dry process, such as metal sputtering, combining with a wet process, such as electroless deposition and then electroplating, is the most popular process now, because the adhesion strength between the metal layer and the PI film is critical. 9,[22][23][24][25][26][27][28][29] Various surface modification approaches of PI were proposed, including dry [29][30][31][32][33][34][35][36][37][38][39][40] and wet 1,4,15,30,36,[40][41][42][43][44][45][46][47][48][49] processes. However, when one considers the process, tools cost, through put, reliability and so on together, it seems difficult to obtain an overall perfect process to achieve the PI surface metallization with a layer of thin copper foil without roughness in between because of the requirement of fine lines and high frequency transmission.…”

“…Several articles had mentioned that copper atoms can diffuse into the modified PI, that is, polyamic acid (PAA), formed by chemical reaction of KOH or NaOH with PI. 44,45,57,58 Therefore, the concept of a barrier layer for blocking copper atoms diffusion was proposed. Currently, the common barrier layer material used for the PI copper metallization is nickel.…”