微电铸器件铸层均匀性的研究

理论分析了负脉冲电流对铸层的修饰作用,采用正负间断脉冲电流和正间断负连续脉冲电流进行了相应的微电铸的实验研究。实验采用的微电铸器件是特征宽度为90 μm的微流控芯片的金属模具。微电铸实验主要包括三个步骤:制作SU-8胶胶模,微电铸和去除SU-8胶。为了对实验结果进行对比分析,两组实验的工作时间和电流强度均采用240 min和2.5 A/dm²。将正负脉冲电流微电铸与正脉冲电流微电铸的实验结果进行了对比分析。研究结果表明,正负间断脉冲电流能够获得较好的器件铸层均匀性。由于在负向脉冲的间断时间内,铸层表面附近的浓度极差得以改变,因此正负间断脉冲电流微电铸的铸层均匀性优于正间断负连续脉冲电流微电铸。实验结果与理论分析结果相一致。

Study on uniformity of micro-electroformed device

A theoretical investigation was presented to explain the effect of pulse-reverse current on the uniformity in micro-electroforming, and the micro-electroforming experiments of two different pulse-reverse currents with gaps were carried out .The two pulse-reverse currents were pulse-reverse current with gaps and pulse-reverse current without gaps in negative current, respectively. The micro-device in the experiments was the mold of micro-fluidic chip with feature width of 90 μm. All experiments consisted of three steps: making of SU-8 resist mold, micro-electroforming and removing of SU-8 resist. With the same working time and average current density, 240 min and 2.5 A/dm², comparison was carried out between the pulse-reverse current experiments and the pulse current experiment. In contrast with the data of pulse-current micro-electroforming, better uniformity was obtained in experiments using the pulse-reverse currents. Because concentration difference over the micro pattern was improved during off-time of the negative current, surface quality was better in the experiment using the pulse-reverse current with gaps. Therefore, the results are consistent with the theoretical investigation.