Chemical Milling

Chemical milling in industry is also known as etching. Chemical milling is a process that uses bases, acids or other chemicals to dissolve unwanted materials such as semiconductor materials, glass or metal. This chemical milling process is used on a wide variety of different metals, and the removal of depths as large as 0.5 inch or 12 mm are achieved. Chemical milling has applications in the semiconductor fabrication and printed circuit board industries, and is also employed in the aerospace industry, to remove thin layers of metal/materials from large aircraft components, such as extruded parts and missile skin panels. There are different types of chemical milling. One is wet etching and another is photochemical etching. Different materials require different types of etchants, for instance, sodium hydroxide is used for aluminium, and ferric chloride or ammonia or ammonium per sulphate is used for copper. Chemical milling is widely used to manufacture integrated circuits, and the semiconductor industry uses plasma etching.