STEP COVERAGE COMPARISON OF TI TIN DEPOSITED BY COLLIMATED AND UNCOLLIMATED PHYSICAL VAPOR-DEPOSITION TECHNIQUES/

The step coverage and grain structure of Ti/TiN films sputtered with a nd without a collimator in a contact/via hole structure were compared using transmission electron microscopy, microelectron diffraction, and Auger electron spectroscopy with field emission microanalysis capabil ity on cross-section samples. ?The holes have widths ranging from 0.40 to 0.75 mu m and aspect ratios from 2.3 to 1.4, respectively. It was found that collimated Ti/TiN films demonstrate reasonably uniform cove rage along the sidewall and at the bottom of hole. Collimated Ti botto m coverage is sufficient to assure good contact resistance. In contras t, uncollimated Ti/TiN films demonstrate an overhang on the top sidewa ll of holes and show decreased coverage when approaching the bottom co rner along the sidewall or along the bottom of holes. Film property di fferences at different regions of a hole using either collimated or un collimated deposition techniques will also be discussed. (C) 1996 Amer ican Vacuum Society.