ELECTROLESS FILL OF TRENCH IN SEMICONDUCTOR STRUCTURE

摘要

A trench in an inter-layer dielectric formed on a semiconductor substrate is defined by a bottom and sidewalls. A copper barrier lines the trench with a copper-growth-promoting liner over the barrier. The trench has bulk copper filling it, and includes voids in the copper. The copper with voids is removed, including from the sidewalls, leaving a void-free copper portion at the bottom. Immersion in an electroless copper bath promotes upward growth of copper on top of the void-free copper portion without inward sidewall copper growth, resulting in a void-free copper fill of the trench.

主权项

1. A method, comprising:
providing a semiconductor structure comprising a copper-filled trench in a layer of an insulating material, wherein the trench is defined by a bottom and walls, and wherein the copper has one or more undesired voids therein; removing a portion of the copper from the trench, the portion including the one or more voids and comprising less than all of the copper in the trench; and electrolessly filling the trench from the bottom upward with additional copper while avoiding copper growth inward from the walls.