THEORETICAL AND EXPERIMENTAL-ANALYSIS OF WIRE SEGMENT HOLOGRAMS FOR STATISTICAL INTERCONNECT METROLOGY

Theoretical and experimental results using computer generated wire seg ment holograms for statistical interconnect metrology are presented. T est structures have been constructed using a process capable of imagin g 1-mu m features and consist of arrays of wire segments illuminated b y a He-Ne Laser. Since the holograms are fabricated at the same time a s actual wires on the wafer, the quality of the projected image correl ates with the emergence of global feature patterning errors, Specifica lly, this paper presents data on the effect of varied exposure time on the intensity of the projected image. An initial statistical analysis indicates that the test structures are capable of detecting variation s in wire geometry which are approximately 1.0% of the nominal wire wi dth, It is anticipated that significant improvements to this level of sensitivity can be obtained by optimization of the holographic encodin g process and test image selection.