Through-mask Electrochemical Micromachining On Molybdenum Grid

Molybdenum is an important structural metal. With these good features of the high melting point,the low density, the low coefficient of thermal expansion, the specific strength, the excellent performance of thermal conductivity and conductive, molybdenum is also on the corrosion of molten glass, molten salt and molten metal. It is widely used in electronic, metal processing, aerospace and other fields.Through mask electrochemical micromachining （Mask electrolysis） combines with theadvantages of both lithography and electrochemical machining, so it can process the complex switchof micron and submicron. It can be used in the thin-walled parts manufacturing of precision grating,VLSI, printed circuit and other metals, and also the part manufacturing of MEMS. However, it is not suitable for molybdenum, because molybdenum is apt to be passivated in the processing of electrolysis. That experimental reaction will increase the difficulty of electrolysis. So, this paperintroduces a H₂SO₄/Methanol organic electrolyte which can solve the passivation problems . This paper uses an organic electrolyte to conduct the study of electrolytic properties onmolybdenum. The following work has been done:1.According to the processing features of electrolytic molybdenum, the experimental apparatus is designed and prepared.2.Researching on the test method and the machining mechanism. Explore the mechanism of passivation and a simplified electric field model is established by finite element analysis tool-ANSYS on molybdenum, that makes a foundation for further parameter optimization.3.In order to obtain optimal parameters, researching on four main factors which can affect the uniformity. Analyze each parameter by taguchi methods.4.Adopting H₂SO₄/Methanol electrolyte, conducted study of electrolytic grid microlithography on molybdenum. Processed into 100μm micro-array structure.The experimental results show that:H₂SO₄/Methanol methanol electrolyte can effectivelyprevent passivation. When using the electrolyte concentration of 20% by volume, the current density is 1.5A/cm²,the cathode diameter is 10mm,the gap between poles is 5mm, the uniformity of molybdenum grid and surface quality are best.