July 11, 2005 – Mitsui Mining & Smelting Co. has developed a technology for etching high density circuits on substrates on which semiconductors used in LCDs are mounted, according to the Nikkei English News.

The technology, developed by adding a special undisclosed ingredient to etching liquid used to melt excess copper foil when making a circuit, enables the space between circuits to be reduced to 20 microns, about 30% smaller than possible with conventional technologies, company sources say.

Mitsui Mining believes the technology will help reduce the weight of LCD TV sets, notebook computers and other products as well as trim the cost of materials used to make them.

The company is set to market semiconductor substrates made with the new technology to chipmakers and other firms. It is also considering selling etching liquid and the new technology to outside companies, the sources say.

Etching liquid containing copper/iron chloride and other substances is used to melt the unneeded copper foil. Mitsui Mining has added a special ingredient to it to enable “vertical shaving” of the foil.

The new technology allows the use of conventional etching methods, making fresh capital investment in chipmaking facilities unnecessary, the sources say.

Mitsui Mining has been selling semiconductor circuits to chipmakers, using substrate materials bought from Sumitomo Metal Mining Co. and Nippon Steel Chemical Co.