Enhancement of Oxidation Resistance and Electrical Properties of Indium-Doped Copper Thin Films

Abstract

Copper thin films with high conductivity and good resistance to electromigration can be used in advanced electronic devices. However, the poor corrosion resistance of copper must be overcome. This work elucidates the possibility of using a self-forming passivation layer to prevent copper oxidation in lightly indiumdoped copper thin films deposited directly on glass substrates and annealed under various oxygen atmospheres. The resistivity of the studied film declined gradually as the film was annealed at an elevated temperature because of the grain growth of the Cu film and the precipitation of indium from the In-doped Cu thin film, as revealed by X-ray diffraction, four-point probe measurements, and transmission electron microscopy. A copper film with high indium content exhibited superior passivation when the film was annealed in an oxygen-rich ambient, but it exhibited high resistivity because of its high indium content. The electrical and passivation properties demonstrated that indium is a promising alloying element for use in copper films for future metallization structures and thin-film transistors.

Laminar Metal Foam: A Soft and Highly Thermally Conductive Thermal Interface Material with a Reliable Joint for Semiconductor Packaging

“…The porosity slightly decreases to 56% because of the addition of a lower density indium layer. Though indium is mainly distributed on the surface (∼8 μm), a thin indium coating (∼1−2 mm) is still found inside the porous copper, which can prevent the copper skeleton from suffering oxidation, 30 as shown in Figure S4a. So we used the SIPC prepared under these electroplating conditions as an experimental sample.…”

A 3 nm Self-Forming InOx Diffusion Barrier for Advanced Cu/Porous Low-k Interconnects

“…[11][12][13] Previous studies found that In has low solubility in Cu, 14) and In doped Cu bulk film can self-form In oxide at the surface to prevent Cu oxidation. 15,16) However, an ultrathin self-forming In oxide serving as a Cu diffusion barrier has not been reported.…”

Study of oxidation process of Cr/Cu/Cr thin film electrodes

“…For example, Koike and Wada [7] have developed Mn-Cu alloy (Mn 0.8% wt) electrodes that can form manganese oxide at the surface of electrode and the electric resistivity as low as 2.0 Â 10 À 8 O cm. The enhancement of oxidation resistance of Cu by alloying with Al [8], In [9], B [10] and Cr [11] has also been reported. Besides, coating a passive film of silver at the surface of Cu grains by wet chemical process can significantly enhance oxidation resistance of copper at relatively low temperatures [12,13].…”