Optimization of SiCOH dielectrics for integration in a 90nm CMOS technology

Low and Ultralow Dielectric Constant Films Prepared by Plasma‐enhanced Chemical Vapor Deposition

“…Results of such an optimization of the properties of SiCOH fi lms are presented in Figures 1.20 [18]. Figure 1.20 shows the FTIR spectra of several dense SiCOH fi lms with k = 2.8-3.0, with mechanical properties improving from V2 to Gen 3 as shown in Table 1.2 [18].…”

“…While SiCOH fi lms are still prepared from different precursors, it was found that superior fi lm properties are obtained when using cyclic precursors TMCTS [40] or OMCTS [18].…”

“…The mechanical properties of SiCOH dielectrics usually decrease with decreasing k values for fi lms deposited by a specifi c processing system (tool and gas mixtures). Nevertheless, the fl exibility of the PECVD process combined with the amorphous structure of SiCOH provides a certain latitude in enhancing the mechanical properties of the fi lms, while retaining the desired low k values [18].…”

“…The apparent lower breakdown fi eld observed in Figure 1.19 for the SiCOH fi lm (k = 2.8) was measured for a fi lm prepared in lab conditions and is not representative for SiCOH fi lms prepared in manufacturing. The latter have been optimized to obtain breakdown fi elds larger than 9 MV/cm [18].…”

“…Despite the general belief that 1 µm fi lms are suffi cient for this characterization, it was found that at this thickness the substrate effect was still signifi cant. That effect was eliminated by measuring fi lms at least 3 µm thick [18]. The cracking propensity of the fi lms and the critical thickness for crack development were determined by a technique described elsewhere [19].…”