The manufacturing of semiconductor¹ wafers（半导体薄片） used in all types of electronics involves etching（蚀刻） small features onto a wafer with lasers, a process that is ultimately limited by the wavelength² of the light itself. The semiconductor industry is rapidly approaching this fundamental limit for increasing the speed of the microchip. The development of a new intense 13.5-nm (extreme ultraviolet or EUV) light source will resolve this issue by reducing the feature size by an order of magnitude or so, according to Purdue researchers in the Journal of Applied³ Physics. One way to generate this wavelength of light is to bombard（轰炸，炮击） tin (Sn) and lithium (Li) targets with laser beams to create an intensely bright plasma⁴（等离子体，血浆） ; Sn and Li are good candidates because their plasmas emit efficiently⁵ in the 13.5 nm region, says Purdue graduate student Ryan Coons. He and his colleagues used spectroscopy（光谱学） and a Faraday cup to analyze⁶ the emission⁷ features and debris⁸ produced in laser-produced tin and lithium plasmas, and others in his group modeled their physical processes.

In a detailed⁹ comparison of the atomic and ionic（离子的） debris, as well as the emission features of Sn and Li plasmas, the group's results show that Sn plasmas produce twice as much emission as that of Li. However, the kinetic¹⁰ energy（动能） of Sn ions is considerably¹¹ higher, though with a lower flux¹². More work is needed to perfect the development of this technology.