Pattern-Dependent Heating of 3D Structures

Spike anneals based on radiation and conduction heating are carried out on silicon wafers with 12xl2mm² patterned areas; these areas are covered with trenches with varying dimensions, thermally isolated from each other by large unpatterned silicon areas. The width of the trenches varies from 150-4500nm; the depths are 400 and 800nm. It is found that lamp-based heating with heatrup rates varying from 50-180degC/s results in temperature gradients of 10-45degC. In case of conduction heating in the conduction-based system (Levitor) no pattern-dependent temperature gradients are observed. A theoretical model was made such as to calculate the temperature gradient generated by the radiation heating process. In case of wide trenches, this model appears to predict the observed gradients reasonably well. However, in case of trenches < 450nm, the model overestimates the experimentally observed gradients.