Towards 3D digital printing of micro-electromechanical systems

Additive manufacturing offers several advantages over conventional methods of production, such as flexibility in design and reduction of required steps during fabrication, leading to faster production times. One promising method for manufacturing complicated 3D devices is based on laser induced forward transfer (LIFT); LIFT is a printing method which allows solid bulk materials to be printed directly. The backside of the supplier material, which is a transparent substrate coated with a thin layer of material, is heated with a pulsed laser and jets a micro-droplet (6-8 um) of the coated material. The ability to print almost any material and the high accuracy and resolution of the droplet deposition gives LIFT a strong potential to be used in printed functional devices. Moreover, in the field of 3D structures this method can contribute to designing novel structures such as multilateral structures and complicated geometries (e.g. hollow cubes). Such structures are very hard to create using conventional methods and can be used for various implementations such as MEMS and micro-batteries. In this paper, we present initial steps towards additive manufacturing of 3D functional devices, by showing 3D metallic micro-structures printed using the LIFT method. In order to print complex 3D structures (e.g. bridges), a sacrificial layer technique was used. Sacrificial layers were printed for support of the desired design and are later removed using a selective etching process, leaving only the required 3D structure.