Development of Porosimetry Techniques for the Characterization of Plasma-Treated Porous Ultra Low-k Materials

Abstract

For the sub-32 nm node, porous SiCOH dielectrics (p-SiCOH) are integrated using dual damascene patterning by etching trenches and vias into the porous material. One challenge is to control the process conditions to minimize the plasma-induced damage of p-SiCOH materials at the bottom and at the sidewall of the trenches. Ellipsometric Porosimetry has been adapted to characterize the plasma-treated materials for both horizontal and vertical surfaces. Since surface modifications can cause adsorption and desorption delays and hydrophobicity loss, porosimetry measurements operated with multi-solvent and kinetic protocols are required. Quantitative measurements of vertically patterned materials are demonstrated using periodic structures of porous material and a Scatterometric Porosimetry analysis. Results show a good sensitivity of the measurement to the different process conditions but also highlight a different impact of the plasma processes on patterned materials compared with blanket films.