基于电铸微凸点形貌演变制作微透镜阵列研究

Research on fabrication of microlens arrays based on micro bump morphology evolution in electroforming

微凸点阵列器件的制备及其一致性是微加工领域的难点问题。使用有限元方法对镍电铸过程中的流场分布、反应离子的物质输运以及电化学反应动力学进行耦合,结合网格变形几何技术,实现了不同电流密度和不同阵列节距微凸点电沉积过程形貌的动态仿真,结果表明:小电流密度有利于形成一致性良好的不同填充比的微凸点阵列。并针对电流密度为1 A/dm2,孔径30μm,深50μm,节距分别为150,180,210μm的微孔阵列进行了电铸实验,得到了不同电铸时间下微凸点阵列的沉积形貌,结果与数值模拟面形演变过程相吻合,同时,所得球面形阵列微凸点的底径误差在5μm以内,表现出很好的一致性。并以金属质球凸阵列为模板,结合翻模技术,提出了一种新的微透镜阵列制作方法。

The fabrication and consistency of micro bump array devices are difficult problems in the field of micro-machining. The shape evolution of the bump arrays with different array space and current density is simulated by the finite-element method based on electrochemical reaction kinetics which takes the flow field distribution and mass transport of reactive ions into consideration. The results shows that the small current density is beneficial to the formation of a good consistency of the bump arrays with different filling ratios. Electroforming experiment on micro-hole with diameter 30 μm,depth 50 μm,array space 150,180,210 μm is carried out aiming at electric current density of 1A/dm2 to obtain the shape evolution at different time. The experimental results and simulation results show good consistency based on the point of view of shape evolution. At the same time,the diameter error of the spherical bump arrays is within 5 μm,showing good consistency. A novel method for the fabrication of microlens arrays has been developed,utilizing the spherical structures gained by electroforming,combined with soft replica molding.