20170213-Nordin-Thesis.pdf (1.9 MB)
Multilayer Surface Inspection Using Gated Wavefront Sensing
thesis
posted on 2017-02-16, 03:56 authored by Nur Dalilla NordinThe
importance of quality control in semiconductor manufacturing process is to
prevent surface roughness, since the behavior of the material is determined by
its surfaces. Recently, multilayer surface profiling and inspection has been
considered an emerging topic that can be used to solve various manufacturing
inspection problems to prevent surface roughness. This thesis develops and
investigates the effectiveness of a multilayer surface inspection system using
gated wavefront sensing approach. The system setup consists of pulse laser,
collimator, beam splitter, well-defined focusing lens, testing specimen, and
gated wavefront sensing assembly (e.g., lenslet and gated camera). By
synchronizing the laser pulses to the camera gate time, discriminating a
multilayer wavefront from its neighboring discrete layer reflections is
possible. The wavefront from different surfaces can be distinguished based on
the range estimation. However, the wavefront can be distorted by the prior
surfaces (reflected wavefront) or post surfaces (transmitted wavefront). As
such a correction method is applied to correct distortion for multilayer
surface reconstruction. The results show that the error is reduced after the
correction technique is applied.