Fabrication of stainless steel mold using electrochemical fabrication method for microfluidic biochip

Abstract

Imprinting method mechanically transfers patterns from a stamp onto a substrate. In imprinting process, the mold is one of the most important factors. A new micro fabrication method termed electrochemical fabrication (ECF) is introduced to overcome conventional problems of electrical discharge machining (EDM), FeCl3 Wet etching, laser method, electro plating, such as low reliability and reproducibility, high cost. This ECF method defines micro patterns using a conventional photolithography, allowing it to produce micro-scale patterns with an excellent surface roughness and of excellent quality. In this paper, a 150 mm stainless steel (SUS 304, 5 turn in thickness) mold was fabricated using both ECF method and FeCl3-etchant method, respectively. As a result, the ECF mold resulted 10 times better surface roughness values than that of mold using FeCl3 etchant. Also, metal surface of the ECF-SUS mold was cleaner and smoother than that the FeCl3 etched SUS mold. Therefore, SUS mold was successfully fabricated for the first time in micro-scale and multi-step patterns. Plastic replica was fabricated successfully using the ECF-SUS mold.