Semiconductor processing Cross section of Dual Damascene (DD) interconnect system in a modern IC. DB: diffusion barrier, ES: Etch stop layer, ILD Inner layer Dielectric. Work of Nabil Mistkawi Chemical Cleaning Solution Atomic Force Microscopy of Copper surface before and after immersion in cleaning solution. Work of graduate student Nabil Mistkawi Selective Ti Etch Formulation Work of graduate student Nabil Mistkawi