Copper electrodeposition from three acidic solutions containing (i) no additive, (ii) 100 pM benzotriazole, and (iii) 100 pM thiourea was studied by in. situ atomic force microscopy. The electrodeposited surfaces were analyzed on three levels: (i) qualitatively during in situ monitoring of morphology evolution, (ii) quantitatively by scaling analysis of electrodeposited surface roughness during the course of deposition, and (iii) by modeling the spectral power density of the surface shape evolution. Major differences in deposit morphology were found between the three electrolytic solutions. All three levels of analysis gave consistent interpretations of morphology evolution. Deposition from additive-free solutions leads to rough surface textures due to roughening originating from surface diffusion. Addition of benzotriazole acts to smooth the deposit by diminishing surface diffusion. Deposits grown from thiourea.-containing solutions exhibit formation of three-dimensional islands atop initially flat plates, reflecting a two-stage growth mechanism.Among the more demanding applications of electrodeposition is the manufacture of microelectronic compo-nents2 which require significant decreases in the dimen.sions of patterned Cu films. Essential to obtaining such deposits with satisfactory textural, mechanical, and elec-* Electrochemical Society Student Member.Electrochernical Society Fellow.

Use of atomic force microscopy (AFM) to image surfaces held under electrochemical control in the presence of fluid flow has been demonstrated. The performance of AFM during fluid flow was evaluated on (i) the atomic level (10 to 200 nm) using cleaved mica as the substrate, (fi) on the micron scale (1 to 12 i~m) using a gold calibration ruling as the substrate, and (iii) on the micron scale during in situ electrodeposition of Cu onto Pt(100). The Reynolds numbers associated with the fluid flow were evaluated by using the diameter and height of the cell as cross-sectional area, and the hydraulic diameter based on the same area as characteristic length. Maximum Reynolds numbers of 8 for atomic imaging (1 to 25 nm) and 130 for larger scales (1 to 12 i~m) may be maintained without loss of imaging quality. The engagement force was the significant parameter which influenced whether images could be obtained during flow. The critical engagement force required for imaging varied linearly with flow rate.Imaging of surfaces by AFM 1 has proven to be ideally suited for in situ study of electrochemical interface phenomena. Demonstrations of the method have to date been made for Cu electrodeposition, 2'3 etching, 4'5 dissolution, 6'7 and corrosion. 8 Since each of these phenomena can be influenced in general by fluid flow, the capability of in situ imaging of convection-dominated processes is of widespread interest. To our knowledge this study was the first to demonstrate feasibility of in situ AFM imaging in the presence of convection.