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

大气压微等离子体射流(APμPJ)由外径为0.4 mm、内径为0.2 mm的不锈钢外科针尖产生，射频激励频率为13.5 6 MHz。钢针既有动力电极的作用，又有气体喷嘴的作用。工作功率为1-6W，对应的峰峰值电压约为1.5KV。利用APμPJ对直径为90μm的铜绕组线的聚酰胺-酰亚胺绝缘膜(厚度为10μm)进行了局部刻蚀。铜线周围的绝缘膜被辐照的等离子体从一定方向完全去除，而不熔断铜线。在射频功率为4W的Ar APμPJ辐照下，去除时间仅为3 S，荧光显微镜和扫描电子显微镜图像显示绝缘层对铜线具有良好的选择性。利用射频外科手术针产生的APμPJ在0.5mmNi线的顶端生长垂直排列的多壁碳纳米管束。采用CH4/H2混合气体作为源气体，以镍丝为衬底，通过离子轰击对其进行负偏压加热。当CH4：H2=1：35，射频功率为6W，直流偏压为-100V，生长时间为2min时，镍丝的顶端覆盖有竹节状的碳纳米管束，直径约为600 nm，长度约为2~3μm。每束约1500根管子，直径10-25 nm。多壁碳纳米管束的生长温度约为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℃.