From Event: SPIE LASE, 2019
Additive manufacturing – specifically 3D laser lithography – is a powerful technology for the fabrication of functional devices on the micro- and nanoscale. This technique has already been applied in a broad range of fields, including metamaterials, biomedicine, and others. While significant progress has being made in chemically tailored photoresist systems for additive manufacturing, the design of photoresists for subtractive manufacturing on the microscale is still in its infancy. Existing resists for 3D laser lithography can only be removed under harsh conditions, such as calcination, oxygen-plasma etching, or etching with hydrofluoric acid.
Herein, we present a new class of on-demand cleavable photoresists for 3D laser lithography. Multifunctional monomers containing disulfide, thioether or silane moieties, which can be specifically cleavage in the presence of a reducing agent or a mild base, are employed. Particularly, dithiothreitol (DTT) causes a thiol–disulfide exchange, erasing the written structure in the first case and sodium bicarbonate (NaHCO3), potassium carbonate (K2CO3) and a fluorine salt (KF) have been proved to sequentially degrade slightly chemically different silane-based microsctructures in the latter case. Thus, these photoresists can be cleaved selectively, which enables the sequential degradation of laser written structures and thereby allows for subtractive manufacturing at the micro- and nanoscale.
© (2019) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Eva Blasco, David Graefe, Markus M. Zieger, Christopher Barner-Kowollik, and Martin Wegener, "Merging 3D additive and subtractive manufacturing on the microscale (Conference Presentation)," Proc. SPIE 10909, Laser 3D Manufacturing VI, 1090905 (Presented at SPIE LASE: February 05, 2019; Published: 4 March 2019); https://doi.org/10.1117/12.2508211.6008593408001.