Research On Electroforming Process For Fabricating Microfludic Metal Mold

Microfluidic chip can be applied to micro-testing, drug delivery (micro-pump, micro-needle), industrial and environmental analysis device, pharmaceutical and life science research, food testing, preparation of new materials, it has huge potential market demand. As important carrier of microfluidics technology, microfluidic chips is to build chemical or biological laboratory on a chip with a few square centimeters, having the advantages of low cost, high efficiency, good portability, high accuracy and so on. But the cost of industrial microfluidic chips is relatively high, based on thermoforming, injection molding process is an important method of producing large quantities of microfluidic chip containing large-scale micro-structures which is the key technology of this process, electroforming as a low-cost large-area micro-structures fabrication technology, can be used to manufact the microfluidic chips metal mold.Considered with microfluidic mold processing requirements, developed a process combining with the phase plate technology, chemical etching and electroforming technology. Process with photolithographic technology to fabricate the mask, then subjected to chemical etching and electroforming processed to achieve microfluidic chip dies. Chemical etching using spray etching machine, electroforming experimental platform is controlled by PID method to achieve precise temperature, cathode fixture is designed as trajectory motion style to increase the uniformity of electro formed cast layer.Electroforming translational cathode, cathode current density, the mask thickness, the secondary auxiliary cathode are carefully studied to investigate their impacts on steep sidewall and deposits uniformity of electroforming microfluidic chip mold microstructures. In order to improve the uniformity of the electrodeposition layer, the experiment is design as a three electrodes electroforming system with a potential secondary auxiliary cathode. Electroforming process focusing factors:etching depth, temperature, mask thickness and the cathode current density, are studied by orthogonal experiment.Micro-chemical etching and micro-electroforming fabrication processes for preparing metal mold of microfluidic chips have been studied. The results show that, mold microstructures fabricated by micro-chemical etching perform irregular curved sidewall, show worse size uniformity and its surface roughness Ra is up to 3.58 μm. By contrast, mold microstructures formed by micro-electroforming perform regular trapezoidal sidewall, show better size uniformity and its surface roughness Ra is only 0.65 μm. In short, microfluidic chips mold fabricated by micro-electroplating is better than micro-chemical etching.Experimental program by controlling the electric power pulse frequency and the pulse waveform, a preliminary study of fabricating micro- and nanostructures on the surface of microfluidic chip mold is launched on. The results show that certain high frequency pulse waveform can achive a certain size of micro- and nanostructures on the surface of microfluidic chip microstructures.