Advanced application of atmospheric-pressure plasma jet using a surgical needle to microfabrication

采用外径为0.4 mm、内径为0.2 mm的不锈钢手术针头，在13.56 MHz的射频激励下，分别产生氩气、氩气/0_2和空气的大气压微等离子体射流（AP μ PJs）。钢针既可作为动力电极又可作为气体喷嘴。工作功率为1 ~ 6w，对应的峰间电压约为1.5 kV。将AP μ PJ应用于直径为90μ m的铜绕组线的聚酰胺-亚胺绝缘膜（厚度为10 μ m）的局部刻蚀。等离子体从一定方向照射铜线后，铜线周围的绝缘层被完全除去，而铜线没有熔断。在射频功率为4 W的Ar AP μ PJ辐照下，去除时间仅为3 s。荧光显微镜和扫描电镜图像显示，绝缘膜对铜线具有良好的选择性。利用射频手术针产生的AP μ PJ，在φ 0.5 mm镍丝的尖端生长了垂直排列的多壁碳纳米管束。采用CH_4/H_2混合气体作为源气体，将Ni丝作为衬底，用离子轰击法负偏置加热。在CH_4:H_2=1:35、RF功率为6 W、直流偏置电压为100 V、生长时间为2 min的条件下，Ni线的尖端覆盖了直径约为600 nm、长度约为2 ~ 3μm的竹状MWNT束。每束由大约1500根直径为10-25纳米的管子组成。MWNT束的生长温度约为500℃。

Atmospheric-pressure microplasma jets (AP μ PJs) of Ar, Ar/0_2 and air were generated from the tip of a stainless steel surgical needle having outer and inner diameter of 0.4 and 0.2 mm, respectively, with a rf excitation of 13.56 MHz. The steel needle functions both as a powered electrode and gas nozzle. The operating power is 1-6 W and the corresponding peak-to-peak voltage is about 1.5 kV. The AP μ PJ was applied to the localized etching of a polyamide-imide insulator film (thickness of 10 μ m) of a copper winding wire of 90μ m diameter. The insulator film around the copper wire was completely removed by the irradiated plasma from a certain direction without fusing the wire. The removal time under the Ar AP μ PJ irradiation was only 3 s at a rf power of 4 W. Fluorescence microscopy and scanning electron microscope images reveal that good selectivity of the insulator film to the copper wire was achieved.Vertically aligned bundles of multiwalled carbon nanotubes (MWNTs) were grown on the tip of a φ 0.5 mm Ni wire using an AP μ PJ generated by a RF-powered surgical needle. A CH_4/H_2 gas mixture was used for the source gas, and the Ni wire used as the substrate was negatively biased to heat it by ion bombardment. At a ratio of CH_4:H_2=1:35,a RF power of 6 W, a DC bias voltage of-100 V and a growth time of 2 min, the tip of the Ni wire was covered by bamboo-like MWNT bundles, whose diameter and length were about 600 nm and 2-3μm, respectively. Each bundle consisted of about 1500 tubes with diameters of 10-25 nm. The growth temperature of the MWNT bundles was approximately 500℃.