FIBLithographie

FIB lithography (focused ion beam lithography) is a maskless nanofabrication technique that uses a focused beam of ions to pattern materials or resists directly on a substrate. In a typical setup, a focused ion beam, often gallium in conventional systems, is scanned over the work surface. Ion irradiation alters the chemical or physical state of a resist, enabling pattern transfer after development, or it can modify the substrate itself through implantation or amorphization. In addition to resist-based patterning, FIB lithography can create features by depositing material from a gas injected into the chamber, a process known as IBID (ion-beam induced deposition), or by milling away material to define structures.

Methods and variants: Resist-based FIB lithography relies on dose-dependent changes in solubility or cross-linking of the resist to define patterns. Direct deposition uses precursor gases that decompose under the ion beam to deposit metals or carbon. Milling or sputtering removes material to sculpt patterns. Helium and neon ion sources (in He- or Ne-FIB instruments) offer higher spatial resolution than conventional Ga-based systems, enabling sub-10 nanometer features in suitable materials.

Advantages and limitations: FIB lithography provides maskless, rapid prototyping and true three-dimensional structuring and is compatible with a wide range of materials. Limitations include slow throughput for large areas, potential beam-induced damage and Ga implantation, redeposition of sputtered material, and requirements for conductive handling of insulating substrates. The technique typically requires vacuum conditions and specialized, costly equipment.

Applications: nanoscale device fabrication and editing, contacts to nanostructures, nanofabrication for photonic and plasmonic components, micro- and nanoelectromechanical systems, and repair or direct-write modification of existing microstructures.

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