Metallfilm

Metallfilm, or metal thin film, is a thin layer of metal deposited on a substrate to alter electrical, optical, or protective properties. Typical thickness ranges from a few nanometers to several micrometers. Metals commonly used include aluminum, copper, nickel, gold, silver, titanium, and chromium; alloys and multilayers are routinely engineered to tune properties such as conductivity, reflectivity, and diffusion behavior. Production methods include physical vapor deposition (PVD) techniques such as sputtering and thermal evaporation, chemical vapor deposition (CVD), electroplating, and electroless plating. Roll-to-roll and other coating processes enable large-area metallfilms on flexible substrates.

Applications are widespread. In microelectronics, metallfilms serve as wiring, contacts, seed or diffusion-barrier layers, and interconnects. In optics, metal films act as mirrors, plasmonic interfaces, or high- and low-reflectivity coatings. In packaging and corrosion protection, they provide diffusion barriers and protective layers. In sensors and MEMS, metal films function as electrode materials and functional coatings.

Key properties include electrical conductivity, optical reflectivity, adhesion, residual stress, and environmental stability. Film thickness, microstructure, and roughness determine performance, while diffusion and oxidation behavior influence longevity. Characterization methods include ellipsometry and X-ray reflectometry for thickness, EDS or XPS for composition, AFM for roughness, and XRD for crystallinity.

Challenges include oxidation of reactive metals, diffusion into substrates, and stress-induced cracking or delamination. Advances focus on nanoscale multilayers for tailored optical responses and barrier performance, as well as transparent conductive metal films and integration with flexible electronics.