AVS 51st International Symposium
    Surface Science Monday Sessions
       Session SS-MoP

Paper SS-MoP36
Electrochemical Micromachining with Ultrashort Voltage Pulses: Modeling and Simulation

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: J. Kenney, The University of Texas at Austin
Authors: J. Kenney, The University of Texas at Austin
G.S. Hwang, The University of Texas at Austin
Correspondent: Click to Email
Recent results using electrochemical systems show promise for the areas of three-dimensional etching, high aspect ratio etching, and controlled deposition. These methods employ a â?otoolâ? electrode held in close proximity (~1 micron) to a reactive â?osubstrateâ? electrode in the presence of an electrolyte and utilize ultrashort (~50 ns) voltage pulses to modify the substrate surface selectively. The shape and feature resolution of synthesized structures would be determined by a complex combination of i) charging and discharging of electrochemical double layers at electrode surfaces, ii) electrochemical reactions on the electrodes, and iii) transport of molecules to the electrode surface. Experiments may provide many clues to the fundamental behaviors of electrochemical systems, but their interpretations often remain controversial due largely to difficulties in direct measurement. While current experimental techniques are still limited to providing complementary real space information, the interplay between experiment and theory will contribute to uncovering intricate kinetic phenomena involved in the electrochemical micron-scale patterning. In this talk, we present our multiphysics computational model for electrochemical micromachining with ultrashort voltage pulses. This approach integrates i) a circuit model to describe charging and discharging of electrochemical double layers and electric field variation in electrolytes and ii) the level set method to simulate feature profile evolution during electrochemical etching. Our simulation results of transient current responses and etch profile evolution are qualitatively in excellent agreement with experimental observations. From our simulations, we find that the resolution of etched features is a strong function of the substrate double layer capacity which may be controlled by electrolyte concentration and pulse duration.