模板微电铸工艺制备金字塔形镍纳米尖

Preparation of pyramidal Ni nano-tips using template-microelectroforming technique

为了获得可靠的金属纳米尖的制作方法,设计了基于模板微电铸工艺制备金字塔型纳米Ni尖的工艺流程并进行了实验验证。利用(100)型单晶硅的各向异性腐蚀特性在40%的KOH溶液中腐蚀以制备倒金字塔型的硅模具,采用磁控溅射与正胶剥离工艺获得了厚度为200 nm的Ni种子层薄膜并进行金属图形化,之后进行微电铸实验,最后,利用KOH腐蚀硅模具以释放金字塔型实体Ni纳米尖。实验结果表明利用ICP干法刻蚀代替HF酸腐蚀SiO2掩蔽窗口,可将模具制作的相对误差降低约9%;金字塔型Ni纳米尖的底部边长尺寸约为140μm,纳米尖最小曲率半径为54 nm;微电铸工艺复制精度约为99%。采用微电铸工艺并结合硅片自停止刻蚀技术,能够稳定可靠地制备出金字塔型Ni纳米尖,实现了金属纳米尖的批量化制备,从而降低了制造成本,为纳米尖的广泛应用奠定了基础。

In order to obtain a reliable method for the fabrication of nanometer metal tips,the fabrication process for pyramidal Ni tips based on microelectroforming technology was designed and verified experimentally.First,silicon templates with inverted pyramidal pits were fabricated on(100)single crystal silicon wafers using anisotropic etching.Then,a 200 nm thick Ni thin film as seed layer was deposited onto the templates by magnetron sputtering combined with lift-off technology,followed by a Ni microelectroforming step.Finally,the pyramidal Ni nanotips were released by etching the silicon template in KOH solution.The results show that the relative error of square etch-windows on the silicon templates can be reduced by approximately 9%using inductively-coupled plasma dry etching instead of hydrofluoric acid etching in the patterning of the SiO2 etch-windows.The bottom side length of the pyramidal Ni nanotip is approximately 140μm,and the smallest radius of curvature of the nanotips is 54 nm.The replication accuracy from the templates to the nanotips reached as high as 99%.The results show that the template microelectroforming technique can be used to achieve stable and mass fabrication of Ni nanotips,which reduces the cost and lays a solid foundation for the application of metal nanotips.