micromachines Review Recent Advances in Reactive Ion Etching and Applications of High-Aspect-Ratio Microfabrication Michael Huff Founder and Director of the MEMS and Nanotechnology Exchange, Corporation for National Research Initiatives, Reston, VA 20191, USA;
[email protected] Abstract: This paper reviews the recent advances in reaction-ion etching (RIE) for application in high-aspect-ratio microfabrication. High-aspect-ratio etching of materials used in micro- and nanofabrication has become a very important enabling technology particularly for bulk microma- chining applications, but increasingly also for mainstream integrated circuit technology such as three-dimensional multi-functional systems integration. The characteristics of traditional RIE allow for high levels of anisotropy compared to competing technologies, which is important in microsys- tems device fabrication for a number of reasons, primarily because it allows the resultant device dimensions to be more accurately and precisely controlled. This directly leads to a reduction in development costs as well as improved production yields. Nevertheless, traditional RIE was limited to moderate etch depths (e.g., a few microns). More recent developments in newer RIE methods and equipment have enabled considerably deeper etches and higher aspect ratios compared to tradi- tional RIE methods and have revolutionized bulk micromachining technologies. The most widely known of these technologies is called the inductively-coupled plasma (ICP) deep reactive ion etching (DRIE) and this has become a mainstay for development and production of silicon-based micro- and nano-machined devices. This paper will review deep high-aspect-ratio reactive ion etching Citation: Huff, M. Recent Advances technologies for silicon, fused silica (quartz), glass, silicon carbide, compound semiconductors and in Reactive Ion Etching and piezoelectric materials.