This paper describes the control and reduction of agglomeration of the thin copper seed layer deposited on different barrier layers. Higher stress is applied in layers deposited on TaN and Ta barrier layers. This stress greatly affects the agglomeration and adhesion strength. This stress can be reduced markedly with employing a TaSiN barrier layer instead of Ta barrier layer. Correlations have been found between the stress in as-deposited copper seed layer and the agglomeration height formed with this annealing. That is, agglomeration occurs markedly in the layer on tantalum nitride ͑TaN͒ and Ta barrier layers. Although lower stress layer can be accomplished at the Cu seed/TaSiN interface, no agglomerations occur in the TaSiN barrier layer. This barrier layer for copper diffusion can also get promising barrier performance.

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Fluctuations of corrosion potential have been analyzed for localized corrosion of Type 304 stainless steel immersed in NaC1 solutions containing NaC10. Potential fluctuations were sampled by a microcomputer, and power spectra were calculated by the fast Fourier transform (FFT). Acoustic emission (AE) was also measured to investigate origins of the potential fluctuations. It was found that formation and repassivation of micropits was confirmed by the potential fluctuations in the form of rapid drop followed by slow rise. When crevice corrosion was proceeding, potential fluctuations in the form of rapid rise followed by slow drop were observed. The absolute values of the slope of power spectral density (psd) for formation and repassivation of micropits were smaller than those for crevice corrosion in the frequency range of 0.01-0.1 Hz.Recently, there has been increased interest in the use of electrochemical noise analysis to investigate localized corrosion of stainless steel. There are two methods for measurements of the electrochemical noise, one of the methods is a measurement of current fluctuations under potentiostatic control, and another one is a measurement of potential fluctuations without external polarization. Most of the electrochemical noise measurements reported have been carried out under potentiostatic control (1-4).However, there is a problem that mechanism of initiation and propagation of localized corrosion under potentiostatic control are different from those of a freely corroded electrode. For example, Steigerwald (5) questioned the physical significance of a critical pitting potential determined by potentiostatic polarization: He reported that pits formed at more active potential than the critical pitting potential during conventional exposure tests. Further, France and co-workers (6) showed that controlled potential tests and conventional chemical corrosion tests did not yield similar rates or types of attack under identical environmental conditions. Schwenk (7) mentioned that pitting corros}on without external polarization is of a potentiostatic character at the beginning; however, pit growth resembles more the phenomena for galvanostatic conditions.Thus, the analysis of current fluctuations under potentiostatic control alone is thought to be insufficient to investigate localized corrosion of stainless steels. Fluctuations of corrosion potential, that is, potential fluctuations without external polarization, also should be analyzed.Stolica (8) observed sharp oscillations of the potential during early stages of pitting on Fe-Cr alloys in 1N H2SO4 containing small amounts of'C1-; their frequency and magnitude depended on the C1 concentration. Schwenk (7) reported that synchronous shaped variations of corrosion potential around a quasi-stationary limiting value are observed during pit propagation. Although fluctuations of corrosion potential during localized corrosion have been observed by several workers, correlations between potential fluctuations and a process of localized corrosion have not ...