Impact of coherence length on the field of view in dark-field holographic microscopy for semiconductor metrology: theoretical and experimental comparisons

Abstract

Semiconductor manufacturers continue to increase the component densities on computer chips by reducing the device dimensions to less than 10 nm. This trend requires faster, more precise, and more robust optical metrology tools that contain complex and high-precision optics with challenging imaging requirements. Here, we present dark-field digital holographic microscopy as a promising optical metrology technique that uses optics with acceptable complexity. A theoretical analysis and an experimental demonstration of this technique are presented, showing the impact of the coherence length of the light source on the field of view. Finally, we also present the first holographically obtained images of metrology targets.