Abstract

The trend towards smaller linewidths and increased component placement accuracies in the fields of printed circuits and hybrid circuits is forcing inspection imaging systems to higher performance levels, especially in terms of resolution and accuracy. Additionally, 3D imaging has been found to greatly aid in the inspection of circuits bearing surface mounted devices. However, surface reflectance characteristics can greatly affect the accuracy of a linewidth or component height measurement. A one-dimensional model is introduced which explains one class of artifacts resulting from scattering of a gaussian beam within the illuminated material.

© 1987 Optical Society of America