Enhanced growth of device-quality copper by hydrogen plasma-assisted chemical vapor deposition

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Abstract
A hydrogen plasma‐assisted chemical vapor deposition (PACVD) process has been developed for the growth of device‐quality copper films on large‐area substrates. The process takes advantage of the high concentration of reactive hydrogen species present in the low‐power plasma to enhance the clean reduction of copper β‐diketonate precursors such as bis(hexafluoroacetylacetonato)copper(II). Copper films were produced at substrate temperatures of 160–170 °C, reactor working pressures of 1.3–1.7 Torr, hydrogen flow rates between 700 and 1200 cc/min, and hydrogen plasma power ranging from 15 to 30 W (with an equivalent power density of ∼0.10–0.25 W/cm2. The films were characterized by x‐ray photoelectron spectroscopy, Rutherford backscattering spectroscopy, scanning electron microscopy (SEM), and cross‐section SEM. These studies indicate that PACVD processes pure, dense, highly uniform films, and allows conformal step coverage and complete hole filling of patterned test structures. Growth rates over large‐area substrates were as high as 1000 Å/min.