Deep reactive ion etching (DRIE) is a type of [[reactive ion etching]] aimed at creating very deep, high aspect ratio structures. While a standard RIE process can be used, they are often inadequate so a couple of variations have been developed for specific applications. The most common variant is the [[/Bosch process/]], used mainly for etching [[silicon]] substrates. It is also possible to use [[/cryogenic etching/]] to create a high aspect ratio etch in silicon, [[compound semiconductors]], and some [[polymers]]. Most dielectrics and metals are significantly more difficult to etch than these materials, so deep etches are uncommon. The LNF has one process for deep etching in [[glass]] and [[fused silica]], known colloquially as ''DGRIE''. An alternative for metals is using [[electroplating]] with a high aspect ratio photoresist, such as [[SU-8]].
==Method of operation==
DRIE processes operate in a similar fashion to [[RIE]] processes, but the process is tuned to be highly vertical and capable of long, deep etches. In particular, high selectivity is necessary, since mask thicknesses are typically limited to less than 10 μm.
==Deep glass etching==
The Oxford Plasmalab is an ICP RIE system capable of cryogenic etching. While not configured to etch silicon, it can etch [[compound semiconductors]] and perform a cryogenic etch of [[polymers]].</onlyinclude>