Alternating Flow Patterns for Copper Plating Uniformity

Abstract

The need for smaller and faster electronic circuits is driving the design of printed circuit board (PCB) interconnects in the direction of finer pitch transmission lines, smaller diameter through holes and vias, and thicker boards with higher layer counts to provide increased circuit densities. Many of the major defects associated with the manufacture of semiconductors and PCBs may be attributed to poor mechanical quality of z-interconnects. Faraday Technology is coupling patented cell geometry with alternating flow schemes to address copper metallization for shrinking interconnect dimensions. Preliminary modeling work provided the initial switching frequency and flow rate targets for the experimental optimization work that is currently underway. This work is anticipated to improve copper metallization uniformity in high aspect ratio z-interconnects, resulting in improved throwing power and mechanical properties as compared to currently available plating cell geometries and agitation mechanisms.

Electrodeposition of Cobalt-Manganese Alloy Coatings onto Metallic SOFC Interconnects

“…The electrolyte flow rate was held constant at ~7.6 LPM and the temperature of the electrolyte was maintained between 30 and 35 °C. in a small scale FARADAYIC ® Electrodeposition cell that is designed to deliver uniform electrolyte flow parallel to the surface of the 441 stainless steel substrate through a channel created by the cathode and anode (11). The ammonium sulfate concentration and pH of the electrolyte were varied and the forward peak current density and waveform frequency were varied in order to ascertain their effect on the coating deposition rate and alloy composition.…”

Improved Uniformity of Conformal Through-Hole Copper Electrodeposition by Revision of Plating Cell Configuration

“…4,5 However, the need for smaller and faster electronic circuits is driving the design of PCB interconnects in the direction of finer lines, smaller hole diameter and thicker lamination with more layers, thereby resulting in the difficulty of uniform copper deposition for higher aspect ratio TH. 6,7 Generally, the copper deposition at the edges and corners of THs is faster than that in the interior due to the uneven current density distribution and difficult mass transfer inside the THs. Therefore, copper thickness is non-uniform along the side wall of the holes especially as the AR of TH increases (i.e., a low uniformity and a copper overhang at the TH mouth).…”