Deep Reactive Ion Etching or DRIE is a highly anisotropic etch process developed in the semiconductor industry and used to create deep and high aspect ratio channels in materials such as silicon. Widely used for MEMS and high value integrated capacitors, channels with vertical sides and having aspect ratios greater than 20:1 can be produced. This article is being considered for deletion in accordance with Wikipedias deletion policy. ... Etching is an intaglio method of printmaking in which the image is incised into the surface of a metal plate using an acid. ... A semiconductor is a material with an electrical conductance that is intermediate to those of an insulator and a conductor. ... The aspect ratio of a two-dimensional shape is the ratio of its longest dimension to its shortest dimension. ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance dark gray, bluish tinge Atomic mass 28. ... // Introduction Micro Electro-Mechanical Systems (MEMS) is the technology of the very small, and merges at the nanoscale into Nano Electro-Mechanical Systems (NEMS) and Nanotechnology. ... Various types of capacitors A capacitor (occasionally referred to using the older term condenser) is a device that stores energy in the electric field created between a pair of conductors on which equal but opposite electric charges have been placed. ... The aspect ratio of a two-dimensional shape is the ratio of its longest dimension to its shortest dimension. ...

There are three primary processes which are brough together to achieve the results in DRIE. First of all a highly reactive gas is used to perform an isotropic etch of the substrate. After a brief period the etching is stopped and the process switches over to deposition of a layer of passivation over the whole surface. This protects the substrate from further chemical attack and prevents further etching. The process now returns to etching, which is where the third process comes into play. Within the chamber there is an energetic plasma which produces a collimated stream of ions that bombard the substrate. By a process of sputtering these ions remove the passivation from the bottom of the previous etch step, but not from the sides. The etchant chemicals can then erode only the bottom of the channels. Isotropic means independent of direction. Isotropic radiation has the same intensity regardless of the direction of measurement, and an isotropic field exerts the same action regardless of how the test particle is oriented. ... The word substrate can mean the following: In biochemistry, a substrate is a molecule which is acted upon by an enzyme. ... Passivation is the process of making a material passive in relation to another material prior to using the materials together. ... The word plasma has a Greek root which means to be formed or molded (the word plastic shares this root). ... Collimated light is light whose rays are parallel. ... An ion is an atom or group of atoms with a net electric charge. ... Sputtering is a physical process whereby atoms in a solid target material are ejected into the gas phase due to bombardment of the material by energetic ions. ...

The process is repeated many times over resulting in a large number of very small isotropic etch steps taking place only at the bottom of the etched pits. It is this selectivity that leads to the overall anisotropy of the process and the creation of high aspect ratio channels with vertical sidewalls. Isotropic means independent of direction. Isotropic radiation has the same intensity regardless of the direction of measurement, and an isotropic field exerts the same action regardless of how the test particle is oriented. ...