w 'est ltdied thefweticall}' [he behavior ofa collapsed persis[errt macromolecule in poor solvent as a model of collapse [ransi[ion ofsingle double-stranded DN.4 chain, and constructed the diugrum ofs[utcr in the variubk~.s ni[h con!our leng~h #a macromolecule and qualit) of the solvent. H'c~,jimnd[hal [he state (? ftoroidat globule e.~is[s as an intermediate state bet nwn the stales (!f elongated coil ,sta[e and the spherical globule. Our [heorc[icai rewdt .suggest.v[hat a single linear macromolecule with a high degree of polymerization can ,jbrm a toroidal globule. H(n~'ever, [he range in~,hich the toroidal structure is stable decreases as the macromolecule Ien,qrh increases. E.rperimtm[al observation u,ith transmission electron microscope>'has been per~iwmed (o stud> tbeglolndar .struclure~fsingle DNA chain (bacteriophage T4 jbund Ihat an twlrernel>' long chain QST4 DN.4 (166 kbp),~~itha contour length of 56 pm, acIually,ftjrm.s a toroidal globule, and that isotropic .vpht~ri

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A W-hardened high-modulus ULK material is proposed for 45-nm-node Cdlow-k interconnects with homogeneous dielectric structures.An elastic modulus as high as 16 GPa was achieved for the ULK material with k=2.65. By combining this material with a n advanced dielectric barrier ( l~3 . 7 1 , interconnect test devices with 65-nm-node dimensions were fabricated.The UV-hardened high-modulus ULK material is shown to be effective in improving electrical performance while maintaining sufficient mechanical integrity.

Dual damascene Cu interconnects with Keff below 2.0 have been demonstrated for the first time. Air gaps between Cu lines were formed with a low K SiOC film in a carefully designed manner. CoWP cap layers were introduced to protect the Cu lines and to eliminate a dielectric liner layer. In addition, AGE (Air Gap Exclusion) was applied to solve crucial problems related to the air gaps. Keff of 1.9 was obtained at 65nm design rule, which surpassed by far ITRS target (2.5 2.8) for hp45. It was also confirmed that leakage current between lines was suppressed by the formation of the air gaps.

Articles you may be interested inOn the pressure effect in energetic deposition of Cu thin films by modulated pulsed power magnetron sputtering: A global plasma model and experimentsThe surface state of copper after an etching process using CF 4 gas has been analyzed. Copper surface stability against corrosion is evaluated through a storage test performed under high-humidity conditions after the etching process. The storage test reveals that the copper surface suffered from both corrosion and oxidation. The copper degradation is caused by a postreaction between moisture and residual fluorine, wherein the resulting oxygen-containing copper film features a rough surface morphology. We examined in situ plasma treatments with several gases to reduce corrosive reactions. Results indicate that in situ N 2 plasma treatment removes fluorine residue from the copper surface, and that this treatment effectively stabilizes the copper surface against corrosive conditions.