Mechanism of Direct Copper Plating on Nonconducting Substrates

Abstract

The mechanism of direct copper plating on nonconducting resin substrates was investigated by high resolution transmission electron microscopy and scanning electron microscopy observation and surface analysis techniques. The substrates were catalyzed by Pd/Sn mixed catalyst and accelerated in an alkaline solution containing copper ions and a reductant before the direct plating. After the acceleration, copper crystalline particles measuring approximately 300 nm were found to be dispersed at the population density of 1.4 ϫ 10 11 m Ϫ2 in addition to adsorbed palladium colloids. The colloids formed clusters measuring 20 to 50 nm which consist of individual particles measuring approximately 2 nm. The addition of copper ions in the acceleration solution exerted a remarkable promotion effect on the speed of lateral propagation of direct plating. This effect can be explained by a modified stepwise propagation mechanism in which dispersed copper particles formed in the Cu(II) containing accelerating solution play a critical role in determining the propagation speed. The copper particles also play an important role in determining the uniformity of the propagation of copper plating.

Patterned Synthesis of Pd4S: Chemically Robust Electrodes and Conducting Etch Masks

“…The rate of deposition on Pd 4 S as well as on Pd films was monitored using EDS quantification. Interestingly, the deposition of Cu is relatively more on Pd 4 S in comparison to Pd, similar to the behavior observed with Pd–S catalysts 33–35. Our observation clearly brings out the catalytic ability of Pd 4 S, thus substantiating earlier speculation in the literature 34…”

“…In order to produce patterns of Pd 4 S, the e‐beam writer available with the SEM instrument was employed. A palladium hexadecylthiolate film (∼60 nm) spin‐coated on a Si substrate was patterned using a 5 kV electron beam at 135 µC/cm 2 and developed in toluene for 10 s. The regions exposed to the e‐beam remained on the substrate after developing, typical of a negative‐tone resist behavior 35. The patterned substrate was subjected to H 2 treatment at 250 °C.…”

Selective Electroless Metallization of Patterned Polymeric Films for Lithography Applications

“…Although lower-dose SAMs will likely become accessible through synthesis or the use of shorter patterning wavelengths (146,148,(163)(164)(165)(166), more reliable vapor-phase deposition (160) techniques may supplant solution-based SAM chemisorption, and lateral metal growth issues may be addressed by anisotropic EL metal deposition methods (167)(168)(169), their compatibility with current manufacturing processes has not been conclusively demonstrated. Therefore, other options for selective EL metal deposition of patterned substrates also need to be explored.…”

Direct Structural and Chemical Analysis of Individual Core−Shell (Pd, Sn) Nanocolloids

“…Pd−Sn Nanocolloids. Pd−Sn nanocolloids in acid suspension are widely used catalysts for the metallization of polymers. , A fundamental question is the structure and surface composition of the colloids. The relatively large enthalpy of mixing (down to −15 kcal/g atom at 320 K near the composition Pd 3 Sn 2 ) indicates the affinity of Pd and Sn; indeed, the Pd−Sn phase diagram exhibits a large number of crystalline alloying phases: Pd 3 Sn, Pd 2 Sn, Pd 3 Sn 2 , PdSn, PdSn 2 , PdSn 3 , and PdSn 4 .…”