Micro Gold Parts Fabricated By UV-LIGA

Gold has many excellent physical and chemical properties, such as plasticity, weldability,corrosion resistance, heat resistance and conductivity, so it is widely used in electronic components、integrated circuits、PCB、space technology and sophisticated military equipment. Because of goodductility, thick micro gold parts are difficult to machine with traditional machining method. UV-LIGAtechnology based on SU-8photoresist is a low-cost manufacturing micro-parts technology, for thisreason micro gold parts with complex shape can be manufactured by UV-LIGA technology.This paper conducts UV-LIGA technology to fabricate micro gold parts research; the followingwork has been done:(1) Flushing fluid electroforming process is researched on fabricating micro gold parts. Manyinfluence factors of micro gold parts surface quality are studied, such as liquid outlet shape, currentdensity and distance between anode and cathode. Optimizing parameters of current density anddistance between anode and cathode are chosen.(2) The relationship between photoresist mold surface width, photoresist mold shape and overexposure process based on SU-8photoresist is studied. And photoresist mold with trapezoidalcross-section is obtained.(3) The swelling law is obtained by researching swelling characteristic of SU-8photoresist ingold sulfite solution. The effect of compensating image line width in mask, designing isolation belt inmask and lowering electroforming temperature on dimension accuracy of micro gold parts isanalyzed.(4) Key dimension of micro gold parts is studied. SU-8photoresist is over exposed by usingimage line width compensation mask. The effect of swelling on key part sidewall is studied.