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Ru-Ta alloy was investigated as the diffusion barrier layer in Cu dual damascene interconnects, and Cu filling property and reliability performances with RuTa/RuTa(N) stacked barrier structure were mainly evaluated. RuTa strongly orientated to Ru(002) and the lattice misfit between Ru(002) and Cu(111) was lower than that between Ta(110) and Cu(111). The wettability of Cu seed on RuTa was much better than that on Ta. The barrier property against Cu diffusion of RuTa/RuTa(N) stacked barrier structure kept the equivalent barrier property of conventional Ta/TaN one. Filling property of Cu electroplating was improved by using Ru-Ta alloy barrier, and trenches of 45 nm in width could be filled successfully due to the suppression of the agglomeration of Cu seed on the sidewall of trench. Via resistance with RuTa/RuTa(N) barrier was much lower than that with Ta/TaN one due to its low resistivity. The estimated life time of via electromigration with RuTa/RuTa(N) barrier was longer than that with Ta/TaN one because of the good wettability and filling property inside via. Consequently, Cu filling property and reliability performance can be improved with RuTa/RuTa(N) stacked barrier structure in Cu interconnects. Copper (Cu) interconnects have been applied to ultra large scale integrated circuits (ULSIs) to reduce the resistance of wiring and resistive-capacitive (RC) delay since the introduction of 130 nm complementary metal oxide semiconductors (CMOSs). As the feature size of trench and via continues to shrink, filling the gaps with Cu electroplating becomes more difficult. For perfectly gap filling, the opening of trench and via after the deposition of barrier and Cu seed have to be kept enough by thinning barrier and/or Cu seed. However, thinning Cu seed leads to Cu being agglomerated on the sidewall of both trench and via where Cu seed is too thin due to its poor coverage, resulting in the formation of voids inside trench and via. Therefore, one challenging issue for Cu interconnects is to fill trench and via completely without the agglomeration of Cu seed on the diffusion barrier layer.New barrier metals that have better wettability with Cu than conventional Tantalum (Ta) have been studied to achieve continuous and smooth Cu film on them.1-26 Among them, Cobalt (Co) and Ruthenium (Ru) have been most frequently suggested for suppressing the agglomeration of Cu seed. Co is known to have the good film properties such as the low resistivity, the high melting point and the good adhesion with Cu. However, Co has the serious problems with chemical mechanical polishing (CMP) process and wet etching process. Co is corroded readily during CMP process and wet etching process, and the slits are occurred between Cu wiring and the interlayer dielectric. It results in the degradation of the device yield and reliability performance. As for Ru, the barrier property against Cu diffusion is not enough, and CMP process for Ru is a difficult technology and the scratch occurred during CMP process leads to the degradation of the device yie...

synopsis13C nuclear magnetic resonance spectra (13C-NMR) of poly(methy1 acrylates) and poly(isopropy1 acrylates) of various tacticities were measured at 25.1 MHz and analyzed. W -N M R spectra of model compounds for poly(methy1 acrylate), poly(acry1ic acid), and poly(sodium acrylate) were also determined. The spectra of the polymers were generally complicated owing to the splittings corresponding to triad, tetrad, or pentad placements, and the assignment for each peak was difficult. Groups of peaks were analyzed by triad or tetrad placements by assuming Bernoullian or first-order Markovian statistics.

The piezoelectric constant of a uniaxially stretched and polarized poly(vinylidene fluoride) film decreases monotonically with increasing temperature in the range from 65 to 165 °C. After a specimen is cooled under open-circuit conditions, the thermally stimulated current reverses in sign and exhibits a peak at around the glass-transition temperature Tg. Reversible changes in infrared spectra before and after the poling process suggest that the dipoles in the β crystals of poly(vinylidene fluoride) can be aligned along the direction of an applied electric field. The alignment is strongly influenced by the amorphous region; the coercive field in P-E hysteresis curve observed at 50 Hz increases rapidly at around Tg. Under a high electric field, the uniaxially stretched poly(vinylidene fluoride) film behaves above Tg in the same way as ferroelectric ceramics.

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