Pratik P. Joshi

Defect Reduction by Nitrogen Purge of Wafer Carriers

Nitrogen purge of wafer carriers is driving defect density reduction at critical process steps. We discuss several examples of defect creation related to the environment of the semiconductor wafer and how nitrogen purge of carriers improves defect density. We have applied nitrogen purge at the gate formation, SiGe epitaxy and silicide formation process steps and we report experimental split data from in line inspection and the result at electrical test. From the impact of the nitrogen purge we can draw conclusions about the nature of defect formation. The impact on volume manufacturing is demonstrated.

Defect reduction by nitrogen purge of wafer carriers

Nitrogen purge of wafer carriers is driving defect density reduction at critical process steps. We discuss the mechanism of defect creation and how nitrogen purge improves defect density. We report on experimental split data from in line inspection and the impact at electrical test. The effect on volume manufacturing is demonstrated.

Systematic edge inspection for defect reduction

We report a systematic radial inspection approach using tilt SEM for wafer apex, bevel and extreme edge to understand structural evolution of floating pattern defects first detected post eSiGe deposition. This investigative method in conjunction with EDS and other such techniques can be very effective in determining point of cause and exact nature of defects, induced due to various process interactions. This in turn can help to eliminate such defects for edge yield enhancement.