Method of preparing an integrated circuit die for imaging

Abstract

Integrated circuit dies are prepared for imaging by completely etching away all metal from the metal lines without removing barrier layers that underlie the metal lines. The metal vias may also be removed, especially if they are formed from the same metal as the metal lines, as in copper damascene circuits. This provides high contrast images that permits circuit layout extraction software to readily distinguish between metal lines and vias.

Description

technical field [0001] The present invention relates generally to inspection and analysis of integrated circuits and, more particularly, to methods of preparing integrated circuit dies for imaging to allow the structure and layout of integrated circuits to be extracted. Background technique [0002] As is well known in the art, inspection and analysis of integrated circuits requires sophisticated sample preparation techniques and imaging tools. In the past, integrated circuits were typically constructed using aluminum for the metal lines in each metal layer of the integrated circuit and tungsten for the vias that interconnect the metal lines, with the components formed on the polysilicon layer. Because aluminum and tungsten can be selectively etched, integrated circuits can be deconstructed using selective etching techniques that enable vias to be separated from metal lines, as will be described in more detail below with reference to FIG. 1 of. In addition, modern integrat...

AI Technical Summary

Problems solved by technology

Circuit layout information is thus di

Images