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Pattern transfer by plasma etching is a traditional standard technology in microelectronics and other micron technologies. These technologies require vacuum conditions, which limit throughput, size, and low-cost fabrication. Recent developments in low cost atmospheric plasma technologies may be suitable to realize pattern transfer without vacuum conditions. Reactive atmospheric plasma jet etching has been used to transfer aluminum mask patterns to fused silica. Aluminum line patterns of 2.5 to 50 µm width on fused silica wafer are exposed to a static as well as a scanning CF4/O2 reactive atmospheric plasma jet with a footprint diameter of 0.85 mm (full width at half maximum), resulting in etching only the SiO2 and causing a nearly isotropic etch with an etch rate of about 200 nm/s. As a result, line narrowing, trapezoidal line cross-sections, and under-etching were observed. The successfully transferred line patterns with the demonstrated widths and depths are of technological interest in various fields of application. Therefore, this approach enables low-cost patterning of fused silica through the use of reactive atmospheric plasma jet etching for micron-scale pattern transfer. This advancement addresses the limitations of both traditional vacuum-based and wet etching methods.

Although laser ablation of polymers is well investigated the achievable surface quality of this process is limited due to laser-induced structural and morphological defects, arising surface roughness and redeposition of debris. Because high quality machining with laser radiation is highly requested, laser-induced plasma etching (LIPE) of polyimide film is studied for the development of ultraprecise surface machining (UPSM) techniques for various applications. Thus, the key parameters such as laser power, etching time, plasma distance of the LIPE are studied experimentally to explore the impact to the etching rate and the surface morphology. LIPE rates as low as 1 pm per laser pulse were measured that fulfil UPSM requirements. The footprint of the LIPE is circular shaped and enable therefore the development of areal processing strategies for surface correction, aspherization and freeform processing. In addition, regular nanostructures that feature a highly regular hexagonal pattern with a period of 117 nm to 125 nm were found at particular conditions.

Dry etching is a prevalent technique for pattern transfer and material removal in microelectronics, optics and photonics due to its high precision material removal with low surface and subsurface damage. These processes, including reactive ion etching (RIE) and plasma etching (PE), are performed at vacuum conditions and provide high selectivity and vertical side wall etched patterns but create high costs and efforts in maintenance due to the required machinery.In contrast to electrically generated plasmas, laser-induced micro plasmas are controllable sources of reactive species in gases at atmospheric pressure that can be used for dry etching of materials.In the present study, we have demonstrated the laser-induced plasma etching of monocrystalline silicon. A Ti:Sapphire laser has been used for igniting an optically pumped plasma in a CF4/O2 gas mixture near atmospheric pressure. The influence of process parameters, like substrate temperature, O2 concentration, plasma-surface distance, etching duration, pulse energy and crystal orientation on etching rate and surface morphology has been investigated.Typical etching rates of 2–12 µm x min−1 can be achieved by varying mentioned parameters with a decreasing etching rate during the process. Different morphologies can be observed due to the parameters set, smooth as well as rough surfaces or even inverted pyramids.The presented etching method provides an approach for precise machining of silicon surfaces with good surface qualities near atmospheric pressure and sufficiently high material removal rates for ultraprecise surface machining.