Nano Machining of Channels by Rubbing at Ultrasonic Frequency Under Control of Surface Fracture at Nano Scale

本项目的目的是提出一种超声频率摩擦纳米加工的方法，并展示纳米通道的制造能力和应用。主要研究成果如下：1.用于纳米加工的集中质量悬臂梁我们研制了一种独特的纳米加工悬臂梁。悬臂在自由端的尖端具有棒状质量。除了平动惯量外，附加的质量还会增加转动惯量。在第二种弯曲振动模式中，由于附加质量的惯性，悬臂的自由端表现为尖端。尖端的垂直运动被抑制，尖端绕附加质量的重力中心旋转。顶端横向振动，并能够感知尖端和样品表面之间的相互剪切力。当附加质量的转动惯量比悬臂梁的转动惯量大4倍时，即使在尖端与试件表面接触的情况下，集中质量悬臂梁的动力学也与单自由度质量-弹簧系统相同。这意味着在循环接触模式下，集中质量悬臂梁能够提供足够的摩擦力。通道的纳米加工虽然抑制了悬臂自由端的垂直运动，但可以检测到偏转角。集中质量悬臂梁采用常规的循环接触工作模式，控制剪力。我们演示了在树脂表面上制作宽度为几百纳米、深度为几十纳米的纳米通道。

The aim of this project is to present a method of nano machining by rubbing at ultrasonic frequency and to show the ability of fabrication of nano channels and the application. The results are summarized as follows:1. Concentrated-mass cantilever for nano machiningWe developed a unique cantilever for nano machining. The cantilever has a rod-like mass on the tip equipped at the free end. The attached mass enhances the moment of inertia in addition to the translational inertia. In the second mode of flexural vibration, the free end of the cantilever behaves like a pined end due to the inertia of the attached mass. The vertical motion of the tip is depressed and the tip rotates around the gravitational center of the attached mass. The tip apex vibrates laterally and is able to sense interactive shear force between the tip apex and a sample surface. When the moment of inertia of the attached mass is 4 times larger than that of the cantilever, the dynamics of the concentrated-mass cantilever becomes the same as that the one-freedom mass-spring system even in the case that the tip is bought into contact with a sample surface. This means that the concentrated-mass cantilever is able to provide sufficient rubbing force when it is used in the cyclic contact mode.2. Nano-machining of channelsAlthough the vertical motion of the free end of the cantilever is depressed, the deflection angle can be detected. The normal operation mode for cyclic contact was applied to the concentrated-mass cantilever, where the shear force was controlled. We demonstrated fabrication of nano channels with a width of a few hundreds of nanometers and a depth of a few tens of nanometers on a resin surface.