Fast Yield Learning Using E-Beam Wafer Inspection

摘要

We report examples of the use of automated e-beam inspection to detect yield or reliability limiting defects which were not seen using conventional optical inspection. In SEM-mode, e-beam inspection affords high resolution and large depth-of-focus to defect detection, making it well suited to inspect sub-0.15μm geometries, even in high aspect ratio structures. This technology can find defects smaller than 0.10μm, even on densely packed, high aspect ratio, multi-layer geometries. Moreover, with the high signal-to-noise ratio inherent in SEMSpec technology, defects that are difficult to inspect optically later in the fabrication process due to grainy polysilicon, grainy metal, underlying structural variations, or dielectric thickness non-uniformity causing color changes, etc are easily observed. Another advantage of SEMSpec inspection is the voltage contrast operating mode, which detects electrical failures/defects not visible by optical techniques.