Graphenic carbon as etching mask: patterning with laser lithography and KOH etching

The wet anisotropic etching process is generally used in the field of micromachining(MEMS), particularly for commercial products such as accelerometers. Hard masks like oxideor nitride play a key role in the transfer of patterns to the substrate during the lithographyprocess. This work reports on the use of polycrystalline graphenic carbon as an etch mask forwet chemical processing and outlines a simple method to create patterned structures on (100)silicon wafers. Graphenic carbon (GC) was deposited on the silicon substrate by chemical vapordeposition (CVD) using C2H4as precursor. The desired pattern was written in the spin-coatednegative photoresist using UV laser lithography. Different geometrical shapes were printed onthe substrate with dimensions ranging from 10 to 50 micrometers. In the next stage, the O2plasma etched away the carbon from the area not covered by the photoresist, acting as anadditional mask for this and the subsequent processing steps. Finally, the sample was immersedin the KOH bath saturated with isopropanol and the etching rate was evaluated for each crystalplane. Compared to the use of a sacrificial oxide mask, this technique is simpler and producesmore reliable results     «

The wet anisotropic etching process is generally used in the field of micromachining(MEMS), particularly for commercial products such as accelerometers. Hard masks like oxideor nitride play a key role in the transfer of patterns to the substrate during the lithographyprocess. This work reports on the use of polycrystalline graphenic carbon as an etch mask forwet chemical processing and outlines a simple method to create patterned structures on (100)silicon wafers. Graphenic ca...     »