The role of copper Damascene additives is discussed based on electrodeposit morphology on a through-mask cathode, field emission-Auger ͑FE-Auger͒, quartz crystal microbalance ͑QCM͒, and electrochemical measurements. Adsorbed particles, several tens of nanometers in diameter were observed on copper-electrodeposited surfaces by field emission-scanning electron microscopy ͑FE-SEM͒. These particles show a stronger oxygen intensity peak by FE-Auger spectrum than bare electrodeposited surfaces. The QCM frequency deviation did not increase with time in the CuSO 4 and H 2 SO 4 bath without polyethylene glycol ͑PEG͒ and chloride ion (Cl Ϫ) additives. When the substrates were immersed in the bath with these additives, the deviation markedly increased with time. Numerous PEG molecules were observed by FE-SEM immersed after 1000 s. The current density remained constant at a low value for the bath with PEG and Cl Ϫ additives. The current density started to increase markedly with time just after adding 1 ppm of bis͑3-sulfopropyl͒ disulfide ͑SPS͒. Numerous PEG molecules were present on the electrodeposits before adding SPS. No PEG molecules, however, remained on the surface once SPS was added to the bath. The current density increased with narrower opening widths of the through-mask cathode. Despite this increase, the deposit cross sections on narrower opening widths of 2 and 10 m were flat and no curvatures were found. Hence, the deposit curvature is not the origin of the acceleration effect.

Copper plate was observed by atomic force microscopy ͑AFM͒ after it was immersed in acid electrolyte with polyethylene glycol ͑PEG͒ and chloride ions (Cl Ϫ ). The AFM image confirmed the existence of adsorbed particles, which are in a flat-cone shape with a bottom radius of 15-25 nm and a height of 2-4 nm. The intermediate complex of copper dissolution/deposition was investigated by means of an electrochemical quartz crystal microbalance through detecting the simultaneous mass change of the electrode during cyclic voltammetric ͑CV͒ measurement. The two current peaks in the CV curves illustrate the generation and consumption of intermediate complex Cu ϩ • Cl Ϫ • PEG on the copper electrode.Nanoscale electrodeposition technologies have been applied to on-chip metallization in recent years. 1-4 As the most promising technology, copper damascene electrodeposition has received growing interest because of reduction in signal delay. In this damascene electrodeposition, a suitable combination of bath additives, e.g., polyethylene glycol ͑PEG͒, Cl Ϫ , bis͑3-sulfopropyl disulfide͒ ͑SPS͒, and Janus green B ͑JGB͒, is required for successful via filling. PEG, together with Cl Ϫ , inhibits the Cu deposition; however, the morphology and potential dependency of the intermediate complex is not known in detail.Regarding the study of the mechanism by which PEG affects damascene plating, Yokoi et al. 5 suggested that PEG traps Cu ϩ on the surface to form an adsorbed inhibiting film. The change of surface concentration of Cu ϩ with potential caused the potential dependency of PEG adsorption, while a Cu ϩ • Cl Ϫ • PEG model was proposed to illustrate how the existence of Cl Ϫ widens the potential region of PEG adsorption. To clarify the morphology of this adsorbed film, many efforts have been made. A Raman spectroscopic study 6 showed that the adsorption of PEG is likely to be in two different forms depending on the potential of the electrode. The investigation of J. J. Kelly et al. indicated that Cl Ϫ ions induce the adsorption of PEG to form a monolayer of spherically packed PEG molecules. 7,8 Field-effect scanning electron microscopy ͑FESEM͒ images reported by Kondo et al. 9,10 showed that particles around 30 nm in diam adsorbed on Cu after it was dipped in an electrodeposition bath containing PEG and Cl Ϫ , and the quantity of the adsorbent increased with the dipping time. Recently, Doblhofer et al. 11 investigated the influence of the inhibiting film on Cu/CuCl/Cu 2ϩ reactions. However, they considered that the inhibiting film forms at the moment that the sample was put into the solution, and no changes of the amount of PEG adsorption with potential and time were considered. In this work, AFM was adopted to further examine the morphology of the intermediate.

Rectal carcinoid tumours are often small and rarely metastatic. Endoscopic resection may, therefore, be the best treatment for small tumours. We diagnosed rectal carcinoid tumours in four women and three men (mean age 53 years; range, 43 -63) between 1994 and 1999. Tumour depth was evaluated using a high-frequency ultrasonographic probe in five of the seven patients. All tumours were resected by endoscopic mucosal resection using an aspiration method with a transparent overcap. Histologically, all tumours were located within the submucosal layer. Tumour cells were found at the resected margin of the lateral side in one patient, and at the bottom of the margin in another. Both patients were followed up with frequent endoscopy, and no local recurrences have been detected at 1-year or 4-year follow-ups. Ultrasonographic examination before resection is useful to estimate tumour depth. Endoscopic resection by an aspiration method with a transparent overcap is safe and effective for the treatment of small rectal carcinoid tumours.

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Pt‐TiOx/C electrocatalysts possess specific activities for the oxygen reduction reaction of about 1.5 times higher than that of conventional Pt/C. Electron‐spin resonance spectra suggest that the specific activity of Pt‐TiOx/C is related to the amount of ESR‐active species.