UV/EB Cure Mechanism for Porous PECVD/SOD Low-k SiCOH Materials

Low‐kMaterials: Recent Advances

“…Overall, both processes are similar in that optimum results are generally obtained at 400 °C with exposures typically ranging from 3 to 10 minutes [71][72][73], the primary difference being that e-beam exposure appears to be more directional as compared to broadband UV exposure [67]. Furthermore, both treatments are equally effective in promoting porogen decomposition at 400 °C [67,68]. For example, XPS data obtained for porogen containing PECVD organosilicate films as a function of UV exposure at 400 °C indicates a rapid decrease in the C/Si ratio during the first 10 minutes of UV exposure, followed by a significantly lower rate of carbon loss [74].…”

“…In order to address these weaknesses, thermally assisted e-beam and ultraviolet (UV) curing processes were auditioned. The goal was to facilitate the complete porogen removal at temperatures ≤400 °C and to boost mechanical properties as a result of the known hardening effect of these treatments [64][65][66][67][68][69].…”

“…Although reactions (d) and (e) cannot be totally ruled out, there is a strong possibility that these may arise from residual porogen fragments left in the organosilicate matrix [67,81]. Finally, reaction pathway (f) has been proposed based on the observed production of Si-H bonds in both UV and e-beam treated organosilicate samples [67,68,81]. This reaction is more predominant in e-beam treated samples.…”

“…In general, broadband UV exposure at 400 °C and exposure times on the order of less than 10 minutes lead to a dramatic improvement in Young's modulus (40-50 % increase) while typically slightly lowering the dielectric constant [68,71,72,79]. However, treatment of multistack structures appears less effective and dictates the treatment of individual layers for optimum results [71].…”

Evaluation of ellipsometric porosimetry for in‐line characterization of ultra low‐κ dielectrics

“…This in situ post treatment is performed by e-beam or thermal assisted UV curing (400 °C) inducing film shrinkage and enabling to achieve a porosity of 29 % with a mean pore radius around 1 nm. UV curing also enhances the mechanical performances of the film, strengthening the Si-O-Si matrix by cross-linking [8].…”