Mechanic Study of Copper Deposition onto Gold Surfaces by Scaling and Spectral Analysis of In Situ Atomic Force Microscopic Images

Abstract

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.

Applications to Magnetic Recording and Microelectronic Technologies

“…different crystallographic orientation, rendering the metal deposit polycrystalline. The mainstream effort to make these polycrystalline films more continuous, uniform, and smoother involves usage of additives considered earlier in this chapter such as PEG, SPS, and thiourea [190,191]. However, along with their positive impact on the growth process, the additives promote the growth of polycrystalline films with relatively high concentration of defects and often contaminated by the additive molecule or by other by-products formed during the deposition process [104].…”

Electrodeposition Science and Technology in the Last Quarter of the Twentieth Century

“…69 Using scanning probe techniques the evolution of deposit morphology in presence and absence of additives was studied with the aim to find scaling laws permitting to relate atomistic growth mechanisms to macroscopic models. 51,63,70 Only a limited number of additives have been studied so far with scanning probe techniques and the different interaction mechanisms between additives are not yet well understood. As scanning probe and other sensitive in situ techniques become more widely used, one may expect that the scientific understanding of how synergistic and antagonistic effects of additives influence electrochemical phase formation will significantly improve.…”

Kinetics of corrosion inhibition of benzotriazole to copper in 3.5% NaCl

“…Benzotriazole (C 6 H 5 N 3 , BTAH) has been extensively studied as an inhibitor for the corrosion of copper and many of its alloys [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16], for dezincification of brass [17,18], and as an additive in the etching [19], electrodeposition [20][21][22], and in the chemical mechanical polishing of copper [23][24][25]. It has also been reported to inhibit the corrosion of iron [26][27][28], cobalt [29], zinc [30], and nickel [28] and to enhance the resistance of tin bronze to oxidation in air up to 500 8C [31].…”