Two-level electrochemical micromachining of titanium for devicefabrication

Abstract

The electrochemical micromachining of titanium structuresrelevant for biomedical applications was studied using a sulfuric acidmethanol electropolishing electrolyte. Single-step etching of large sizedcavities was performed and the effect on the dissolution depth of thepresence of features of different sizes was evaluated. The fabrication oftwo-level structures by a two-step process was studied using consecutivedissolution steps through patterned photoresist masks. Two differentstrategies were compared for producing a model geometry consisting of a10 mm diameter, 10 µm deep, flat-bottomed cavity containing a grid of30 µm grooves. Results show that it is possible to fabricate thetwo-level model geometry by either first etching the cavity or the grooves.For the latter approach a numerical simulation of the shape evolution ofthe grooves during cavity etching permitted us to identify the most usefulprocess window.