The two pieces of equipment requested in the LEAF project constitute a very complete laser processing cluster that has no equivalent in the national RENATECH network. Equipment 1 is a laser micromachining platform based on photo-thermal ablation that will be located at IEMN. Equipment 2 is a high-definition laser lithography platform that will be located at LAAS.

Equipment 1 – Laser micro-structuring by photo-thermal ablation

The first requested equipment is a multipurpose, advanced laser micromachining system to develop original processes of material structuring compatible with properties of flexibility, conformability and stretchability of the substrate. Over the past decades, laser micromachining has emerged as a key technology for structuring, ablating, scribing, cutting, drilling a wide range of materials as diverse as semiconductor crystals, metals and plastics. Because laser photo-thermal ablation enables the direct-write fabrication of complex micro and nanostructures, it is expected to speed-up the demonstration of innovative systems without having to overcome inextricable process and material compatibility problems that we have to face in our recent research activity. Another decisive advantage of laser micro-structuring by photo-thermal ablation is to gather in a single low temperature and chemical-free processing step what is commonly achieved in four steps (resist spin-coating, lithographic exposure, development and etching) with four conventional microtechnology equipments. To achieve spatial resolution without suffering from collateral damage such as HAZ (heat affected zone), a major prerequisite is to integrate high intensity picoseconds laser lines to get access to clean ablation mechanisms. To offer a maximum flexibility, the equipment is based on a direct write method in vector scanning mode using fast galvanometer beam deflection and high repetition rate.

Equipment 2 – Laser 3D lithography and photo-induced transformation

The second piece of equipment is a very high-definition laser lithography machine. This equipment, in up market version, allows to write in ultraviolet photosensitive layers with a laser source emitting at 325nm, 375 nm or 405 nm. Writing surfaces can extend up to 12 inches with the same resolution quality on the whole surface. A high resolution optical head allows writings which resolution can go down 500nm on thicknesses from 5μm and more, with edge at 90°. The specific optical treatment is compatible with a write onto thick layer thanks to the large depth of focus up to several tens of microns to several hundred microns, depending on the resolution. In all case, a minimum aspect ratio up to 10 is guaranteed. It is a completely customized, compact direct laser lithography system, designed for fast prototyping of masks and patterns in Industrial and R&D settings. This system is ideal for rapid design turnaround in applications such as integrated optics, MEMS, microelectronics, microfluidics, diffractive/refractive micro optics and other high resolution microstructuring applications. It is configured with one laser source at any of the four wavelengths of 325 nm, 375 nm (UV) 405 nm and 266 nm, allowing the user to expose most commercially available photoresists. This laser source is fixed, which guarantees both the stability and reliability of the optical alignments during the writing process. Several laser sources can be installed into the same systems. So it is possible to use several laser sources with different wavelength, depending on the application. This makes it compatible, for example, with the multiphoton writing mode, tridimensional microstructuration and all type of photoresists provided in the market place. The laser source is routed through a dedicated optical sub-assembly referred to as the optical tube, which cleans, homogenizes and shapes the laser beam to the needed dimensions in order to achieve high resolution writing. This specific optical treatment induces the large depth of focus which allows the write onto thick layer with a large aspect ratio (up to 10).