Electron energy loss spectrum application for failure mechanism investigation in semiconductor failure analysis

Abstract

Electron energy loss spectrum (EELS) is widely used for material science analysis (F. R. Chen at al., 1998)(D. B. Williams et al., 1996), such as analyzing material elemental analysis and chemistry compound (Y. Mitsui et al., 1998)(M. Shimada et al., 2005). In semiconductor failure analysis, EELS provides clear evidence for investigating and identifying failure mechanisms and root cause discussions. There are three failure analysis cases in this article. The first one is the nearest atomic number failure analysis. The Z contrast of TEM image is not easy distinguished from Al (13), Si (14), which is obviously identified by EELS Al-K(1560ev) and Si-K(1839ev). [5] The second case is realized from the EELS result, the failure mechanism is silicon dioxide residue that resulted in a transistor out of specification. The third case is a barrier bridge identified by EELS mapping. From the EELS evidence, the root cause is identified as a insufficient tungsten back chemical mechanical polishing (W-back-CMP). Based on clear identification, the EELS application for failure mechanism investigation is very useful and helpful in Semiconductor Failure Analysis.