Fabrication of metal microfluidic chip mold with coplanar auxiliary cathode in the electroforming process

Abstract

Thickness nonuniformity is one of the prominent problems in the electroforming process of the metal microfluidic chip mold, which decreases the dimensional accuracy of the mold, and has a direct influence on the usability of the microfluidic chip. A novel method of auxiliary cathode for improving the thickness uniformity of electroformed mold is presented in this paper. Compared with the traditional method of the auxiliary cathode, a coplanar auxiliary cathode similar to the local microstructure of mold is used to fabricate the electroformed mold, and the thickness uniformity of electroformed mold is improved obviously. In addition, in order to determine the dimensions and placement of the auxiliary cathode, the computer-aided analysis is performed to simulate electroforming process. The simulated results show that with the help of a specially designed auxiliary cathode, the thickness uniformity is improved by about 53.2% compared with the result without the auxiliary cathode. Finally, based on the simulation, a microfluidic chip mold is fabricated by micro electroforming with the coplanar auxiliary cathode. The result shows that the thickness uniformity of the mold is improved by about 49.1%, which is in good agreement with the simulation result.