[1] Ground-based measurements of aerosols and trace gases were conducted at an urban site in Tokyo (Komaba) and a site 50 km to the north (Kisai) during July -August 2004. An Aerodyne aerosol mass spectrometer (AMS) was deployed at each measurement site to investigate the chemical evolution of submicron organic aerosol (OA) in polluted air. The mass concentrations of OA at the Kisai site were systematically higher than those at the Komaba site and were correlated with ozone under southerly conditions. The rate of increase of OA at the Kisai site is investigated using the photochemical age derived from the ratio of alkyl nitrates to their parent hydrocarbons. The OA concentrations in processed air (age of 8 -16 h) were 4 -5 times larger than those in fresh emissions (age $ 0), suggesting that the OA concentrations can be significantly enhanced within $0.5 days under conditions of high photochemical activity.

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Physical and chemical properties of plasma-polymerized SiOCH films were investigated using ring-type siloxane monomers with several kinds of side-chain chemicals, and a design principle of the material and plasma-process was derived to obtain a porous SiOCH film of k Ͻ 2.5 with sub-nanometer-scaled porous structure framed by the original ring siloxane backbone. Here, the backbone siloxane structure is fixed as a six-membered Si-O ring of the 0.35 nm, and no progen gas and no post-cure-process were utilized. It was found that unsaturated hydrocarbon side chains such as vinyl increase the deposition rate, and the original monomer structure tends to be kept, reducing the dielectric constant with the porous structure. Large alkyl groups increase the hydrocarbon content in the film as well as the deposition rate. The low radio-frequency power plasma with high precursor concentration also helps the original chemical structure to be preserved. The best solution is to use the ring-type siloxane with both of the vinyl ͑unsaturated hydrocarbon͒ and the large alkyl ͑saturated hydrocarbon͒ under the low-power plasma condition with the high partial pressure of the precursor. The plasma-polymerized porous SiOCH film is a strong candidate for the low-k film in scale-down 45/32 nm node ultralarge-scaled integrated interconnects featured by the simple and low-cost fabrication processes.The scaling of complementary metal oxide semiconductors ͑CMOS͒ device dimensions has contributed to the high-speed operation and extensive integrity of ultralarge scale integrated ͑ULSI͒ devices. 1 These features are achieved by scaling of not only metal oxide semiconductor field-effect transistors ͑MOSFETs͒ but also interconnects. The interconnect performances such as the resistancecapacitance ͑RC͒ time constant, cross-talk, and power consumption, however, have been degraded by the square of the scaling factor due to the parasitic capacitance increment. 2 One approach to reduce the capacitance is introduction of low-k materials into the intermetal dielectrics ͑IMDs͒. Low-k films such as LO-x ͑k = 3.0͒, 3 rigidSiOCH ͑k = 2.9͒, 4 and porous-SiOCH ͑k = 2.6͒, 5,6 have been introduced as IMD for 130, 90, and 65 nm node devices, respectively.Carbon-doped silicon oxides ͑CDOs͒ are one of the well-known low-k materials comprised of Si, O, C, and H. 7-12 The Si-C bonds in CDOs are more covalent than the Si-O ionic ones, because Si and O have large difference in their electronegativity, increasing the ionic polarization, or essentially the dielectric constant. Recently, CDOs have been shown to have pseudo-porosity in the dense cross-linked SiO 2 lattice by chemical decoration of the Si atoms with sterichindered alkyl groups, reducing the film density or eventually the k value. Plasma-enhanced chemical vapor deposition ͑PECVD͒ and spin-on deposition ͑SOD͒ are used for the CDO deposition. The PECVD utilizes gas-phase chemicals in a vacuumed reactor to produce high-quality films in a controllable system. For the PECVD CDO films, SiH 4 /hydrocarbon gas mixture,...

Damage-less full molecular-pore-stack SiOCH (MPS) / Cu interconnect is developed to reduce effective k-value (k eff ).MPS with high endurance against plasma processes is introduced into both via and trench dielectrics without hard mask (HM). Low friction slurry and chemical modification of MPS surface by He-plasma treatment suppress defect generation during direct CMP of the MPS surface. The full-MPS interconnect with low-k (k=3.1) cap demonstrates 10% lower inter-line capacitance and 34% lower inter-layer capacitance than the full-SiOCH (k=3.0) interconnect with SiCN-cap (k=4.9). The effective k-value k eff reduces to 2.67 for the damage-less full MPS structure which is applicable to 32nm LSIs and beyond.

High performance Cu dual-damascene (DD) interconnects without process-induced damages are developed in porous SiOCH stacks with the effective dielectric constant ( e ) of 2.95, in which a carbon (C)-rich molecular-pore-stacking (MPS) SiOCH film ( = 2 5) is stacked directly on an oxygen (O)-rich porous SiOCH ( = 2 7) film. The novel etch-stopperless structure is obtained by comprehensive chemistry design of C/O ratios in the SiOCH stack and the etching plasma of an Ar N 2 CF 4 O 2 gas mixture technique. Large hydrocarbons attached to hexagonal silica backbones in the MPS-SiOCH prevent the Si-CHx bonds from oxidation during O 2 -plasma ashing, suppressing the C-depleted damage area at the DD sidewall. Combining multiresist mask process with immersion ArF photolithography, strictly controlled Cu DD interconnects with 180-nm pitched lines and 65-nm-diameter vias are obtained successfully, ready for the 300-mm fabrication.