End‐point detection by sputtered neutral mass spectrometry in ion milling of prepatterned semiconductor and high‐T_c superconductor films

We explore the use of sputtered neutral mass spectrometry (SNMS) for semiconductor and superconductor device processing. SNMS allows us to precisely determine the end point at interfaces during sputter etching of prepatterned semiconductor and superconductor thin films. By postionizing the sputtered neutrals the detection sensitivity is similar for all elements. The dynamic range of up to three orders of magnitude makes precise end‐point detection possible even if the mask allows sputter etching of only a small fraction of the surface of the specimen.