Etching (microfabrication) - Wikipedia
Etching is used in microfabrication to chemically remove layers from the surface of a wafer during manufacturing. Etching is a critically important process module in fabrication, and every wafer undergoes many etching steps before it is complete.
The basic etching mechanism in the isotropic etching of Si is divided into the oxidation of silicon using nitric acid and the etching of the oxide constantly formed on the surface from this with hydrofl uoric acid:
A comprehensive review on convex and concave corners in silicon …
2015年5月27日 · Two-step etching method is employed for the fabrication of perfect convex corners. Since the perfectly sharp convex corner is formed by the intersection of {111} planes, each step of etching defines one of the facets of convex corners.
Intersection of {111} planes can cause self-limiting etch. If there is no chemical reaction at all, the technique is called ion milling.
KOH etching is a well-documented anisotropic Si etch process. The process most often takes advantage of the etching ratio between the crystal planes in the silicon lattice. The sidewalls of the etch are defined by the <111> plane, and the <100> plane is etched at a 54.7o angle relative to the <111> plane.
The (110) plane is the fastest etching primary surface. The ideal (110) surface has a more corrugated atomic structure than the (100) and (111) primary surfaces. The (111) plane is an extremely slow etching plane that is tightly packed, has a single dangling-bond per atom, and is overall atomically flat. As shown above,
The degree of anisotropy (= etch rate selectivity between different crystal planes), the etch rates, and the etching homogeneity depend on the etching temperature, atomic defects in the silicon crystal, intrinsic impurities of the Si crystal, impurities (metal ions) by the etchant, and the concentration of Si-atoms already etched. The doping ...
High speed silicon wet anisotropic etching for applications in bulk ...
2021年2月22日 · Wet anisotropic etching is extensively employed in silicon bulk micromachining to fabricate microstructures for various applications in the field of microelectromechanical systems (MEMS). In addition, it is most widely used for surface texturing to minimize the reflectance of light to improve the efficiency of crystalline silicon solar cells.
Most often KOH and TMAH etches are used to etch the (100) plane, forming the membranes, V-grooves and other structures. The side walls of the etch are defined
Potassium Hydroxide (KOH) is an alkali hydroxide used in an anisotropic wet-etch technique and is one of the most commonly used silicon etch chemistries for micromachining silicon wafers. Anisotropic etches attack the substrate preferentially.