Thermal Scanning Probe Lithography (t-SPL) is a 3D direct-write lithography technique that provides sub-10nm resolution with sub-2nm vertical accuracy in ambient conditions. A 1,000°C cantilevered tip sublimates PPA resist as it scans over a sample, before the tip quickly cools to provide real-time topological AFM-type characterisation.The process isn’t reliant on an ion gun or electron beam (helpful when processing sensitive materials);it operates at ambient temperature, pressure, low voltage, and under N2 atmosphere instead of requiring a specialist environment. The ease of use and high resolution means it is ideal for rapid fabrication of three-dimensional nanostructures including the fabrication of novel devices and components for nanophotonics, nanooptics, nanoelectronics, and plasmonics applications.
Focused Ion Beam (FIB) milling provides significant advantages as a single-step, nanoscale prototyping method that doesn’t require a mask or resist. It is capable of performing: subtractive lithography in which atoms are locally milled away by physical sputtering with sub-10nm resolution; additive lithography in which materials are locally deposited with sub-10nm resolution; local ion implantation for fabrication of an etching mask for subsequent pattern transfer; and direct material modification by ion-induced mixing.FIB milling is a versatile technique with a wide range of applications including advanced materials development/characterisation; resist-free, high-resolution patterning of nanostructures; cross-sectional analysis of samples; sample preparation for transmission electron microscopy (TEM) and for atom probe analysis.
Electron Beam Lithography (EBL) allows users to write patterns with extremely high resolution, smaller than 10nm in size. It makes use of a highly energetic, tightly focused electron beam, which is scanned over a sample coated with an electron-sensitive resist. The electron beam scans the image according to a pattern defined on a CAD file. The sample is then developed in an appropriate solvent which reveals the structures defined into the resist. This acts as a mould for subsequent pattern transfer techniques such as dry etching ormetal lift-off.Due to the high-resolution nature of the technique, EBL has a vast range of applications including nano-electronics, photonics, plasmonics, nano-fluidics, MEMS, x-ray and neutron optics.
Laser processing uses a highly controlled and focused beam of high-energy photons of the same wavelength to burn away material. These processes are repeatable, scalable and cheap, but can induce thermal stresses on the substrate, and resolutions tend to be in the micrometre regime.Laser processing is often used within ANFF to create masks for later lithography steps, but it can also be used to create patterns directly into the substrate itself, skipping several ordinary fabrication steps.