This page discusses the industrial applications of the etching process. For etching in art or printing ,see etching The Bath, a painting by Mary Cassatt (1891-1892). ... This article or section is in need of attention from an expert on the subject. ... Etching is an intaglio method of printmaking in which the image is incised into the surface of a metal plate using an acid. ...

Chemical etching (sometimes called chemical milling or wet etching) is the process of using acids, bases or other chemicals to dissolve away unwanted materials such as metals, semiconductor materials or glass. It has applications in the printed circuit board and semiconductor fabrication industries. A Miller is a person who operates a mill for grinding material and usually refers to one who grinds a cereal crop to make flour. ... For other uses, see Acid (disambiguation). ... A bases in chemistry is a chemical substance which has a free pair of electrons to bind a Hydrogen ion commonly referred to as a proton (IUPAC definition). ... A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ... Hot metal work from a blacksmith In chemistry, a metal (Greek: Metallon) is an element that readily forms positive ions (cations) and has metallic bonds. ... A semiconductor is a solid whose electrical conductivity can be controlled over a wide range, either permanently or dynamically. ... Close-up photo of one side of a motherboard PCB, showing conductive traces, vias and solder points for through-hole components on the opposite side. ... A semiconductor is a solid whose electrical conductivity can be controlled over a wide range, either permanently or dynamically. ...

Etchants

There are two kinds of etching etchants, isotropic etchants and anisotropic etchants: 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. ... This article is being considered for deletion in accordance with Wikipedias deletion policy. ...

• Isotropic etchants attack the material being etched at the same rate in all directions.
• Anisotropic etchants attack the silicon wafer at different rates in different directions. On wafers the most used etchant is KOH. By doping silicon with high concentrations of boron it becomes unetchable. This technique is termed an etchstop. See footnote for further information.

Anisotropic etching does not cause undercutting, and is preferred in applications where straight side walls are essential. Anisotropic etching requires a substrate with a well defined crystalline structure such as silicon. The etch is directional and proceeds along the exposed plane in the crystal lattice. As atoms are removed from the crystal lattice, different planes are exposed to the etchant. Since the density of atoms on the planes varies, the etch rate varies significantly. A rate is a special kind of ratio, of two measurements with different units. ... A right-handed Cartesian coordinate system, presenting the z (up) vector and y (forward) vector, the right is defined to be the positive x vector. ... The chemical compound potassium hydroxide, (KOH) sometimes known as caustic potash, potassa, potash lye, and potassium hydrate, is a metallic base. ...

Footnote: http://www.techneglas.com/dopantpages/etch.htm

History of etching

The process is believed to have been invented by Daniel Hopfer (circa 1470-1536) of Augsburg, Germany, who decorated armour in this way, and applied the method to printmaking. Events May 15 - Charles VIII of Sweden who had served three terms as King of Sweden dies. ... Events February 2 - Spaniard Pedro de Mendoza founds Buenos Aires, Argentina. ... Armour or armor (see spelling differences) is protective clothing intended to defend its wearer from intentional harm in combat and military engagements, typically associated with soldiers. ... Printmaking is a process for producing editions (mutliple copies) of artwork; painting, on the other hand, is a process for producing a single original piece of artwork. ...

Explanation

Etching is used in the manufacturing of printed circuit boards and h Close-up photo of one side of a motherboard PCB, showing conductive traces, vias and solder points for through-hole components on the opposite side. ...

Etchants

Commonly used etchants for copper are:

• Ferric chloride
• Ammonium persulfate
• Ammonia

Ferric chloride (FeCl3) is an iron-based salt. ... Ammonium persulfate (NH4)2S2O8 has been prepared by H. Marshall by the method used for the preparation of Potassium Persulfate. ... Ammonia is a compound of nitrogen and hydrogen with the formula NH3. ...

Etching of metals

Etching of glass

Hydrofluoric acid (HF) is a very efficient etchant for glass. It is however very dangerous if it comes into contact with the body. Flash point -37. ... Glass can be made transparent and flat, or into other shapes and colors as shown in this sphere from the Verrerie of Brehat in Brittany. ...

Etching in the semiconductor industry

Semiconductor etching is divided into two major categories, isotropic and anisotropic. 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. ... This article is being considered for deletion in accordance with Wikipedias deletion policy. ...

• Plasma Etching
• RIE
• DRIE

Reactive ion etching (RIE) is a technology using plasma to etch material deposited on wafers. ... DRIE or deep reactive ion etching is a dry etching technique used for creating high aspect ratio structures in micro fabrication. ...

Applications

See also

Electroplating Electroplating is the coating of an electrically conductive item with a layer of metal using electrical current. ...

External links

• Precision Photo-Fab, based in Buffalo, NY, is a leader in the chemical etching industry.

• Example of a chemically-etched nameplate manufacturer who has won the Baldrige Award for quality twice, in 1998 and 2004
  

• Worldwide suppliers of Chemically etched parts Hi-Rel Lids Ltd.