Gate oxide layer failure analysis method

Abstract

The invention discloses a gate oxide layer failure analysis method; a prepared TEM sample is bombarded by using an ionic beam having certain energy, Poly in the TEM sample is non-crystallized, the Poly lattice contrast cannot be showed in a transmission electron microscope, the contrast of heavy metals still remains, heavy metal polluted positions can be clearly observed under the transmission electron microscope, elemental analysis is successfully carried out, and thus the gate oxide layer failure analysis efficiency is effectively improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a failure analysis method for a gate oxide layer. Background technique [0002] In the process reliability test (Process reliability test), there will be a problem of gate oxide integration failure, that is, the breakdown voltage of the gate oxide layer is low and the leakage is large. A common cause of this failure is heavy metal contamination, which usually requires microscopy and elemental analysis to determine the source of the contamination. When using a focused ion beam microscope (FIB) for sample preparation, it can be clearly seen that there are heavy metal residues between the polysilicon gate (Poly) and the gate oxide layer (gateoxide), such as figure 1 As shown, heavy metal residues1 can be clearly seen between the polysilicon gate and the gate oxide layer under a focused ion beam microscope (FIB), but FIB cannot perform accurate elemental analysis...

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Problems solved by technology

[0005] In view of the above existing problems, the present invention discloses a gate oxide layer failure analysis method to overcome the indistinguishability of the contrast in the transmission electron microscope due to the uncertain lattice contrast of Poly and the indistinguishability from the contrast of heavy metal elements in the prior art. The problem of clearly observing the position of heavy metal contamination, which makes it impossible to carry out elemental analysis

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