Why is copper locally etched by scanning electrochemical microscopy?.


Sheffer M, Mandler D. Why is copper locally etched by scanning electrochemical microscopy? J. Electroanal. Chem.Journal of Electroanalytical Chemistry. 2008;622 (1) :115 - 120.

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The etching of thin Cu films by scanning electrochem. microscopy (SECM) was studied. It is not trivial that locally injected charge by an oxidized mediator will lead to dissoln. of Cu as the charge can easily be dissipated by lateral charge propagation. The authors studied the effect of different parameters, such as thickness of the Cu film and concn. of the mediator, on the efficiency of etching. The feedback current is the sum of 3 charge transfer contributions: diffusion of mediator species, chem. reaction on the surface and lateral charge propagation across the Cu film. The authors have introduced an approach for isolating the lateral contribution and studied the parameters affecting the fate of the locally injected charge. Etching becomes effective once the lateral contribution cannot dissipate the locally injected charge. This occurs as the concn. of the etchant increases or the film thickness decreases. Measuring the steady-state current above Cu films with different thickness, allowed estg. the p.d. across the Cu area underneath the tip. Driving local processes, such as etching, depends on creating a mechanism which maintains the injected charge focused. [on SciFinder(R)]


CAPLUS AN 2008:1109078(Journal)