Bottom-Up Filling in Electroless Plating with an Addition of Janus Green B and Triblock copolymers PEP-3100

The bottom-up filling of electroless copper usually depends on inhibiting the surface deposition of electroless copper or accelerating to achieve a relative high deposition rate of electroless copper in the bottom of trenches. In this paper, a bottom-up filling of electroless copper, in which the deposition rates of electroless copper were inhibited at the surface of the substrate and accelerated in the bottom of the trenched, was designed and achieved in the bath with an addition of Janus Green B (JGB) and Triblock copolymers PEP-3100. The cross-section SEM observation indicated that all trenches with different widths ranging from 130 to 520 nm were filled completely by electroless copper and no void was found. This was attributed to synergistic effect of three factors, addition JGB only in the bath accelerated Cu deposition markedly; addition bath JGB and PEP-3100 in the bath decreased Cu deposition sharply; the large molecular weight and lower diffusion coefficient of PEP-3100 resulted in concentration gradient of PEP-3100 in the trenches. The effects of PEP-3100 and JGB on both cathodic and anodic reaction were demonstrated by linear sweep voltammetry (LSV) method.