Evidence for "superfilling" of submicrometer trenches with electroless copper deposit

Void-free copper filling of trenches for ultralarge scale integrated interconnect structure was demonstrated by electroless deposition technique using polyethylene glycol as an inhibiting bath additive. With this electroless plating bath, the authors succeeded in demonstrating superfilling. Of particular interest is that the deposition at trench opening was nil during the filling process, while that at the bottom was very fast. This letter presents a demonstration and a proof of superfilling of trenches by electroless copper deposition.