Micro-machining of metal surfaces by scanning probe microscope

首先，我们构建了一个用于微加工研究的扫描探针显微镜(SPM)系统。SPM系统由SPM单元、大气控制装置和测控系统组成。其次，我们研究了在悬臂梁末端安装了一个非常锋利的钻石尖端的扫描探针显微镜在空气中对纯金属表面的微加工。用气相沉积或机械抛光的方法制备了纯金属样品，如镍、铜和金。用0.5-3微米x向宽度和0.5-20微米载荷的x-y扫描对样品表面进行划痕，用同样的扫描电子显微镜观察划痕区域的形貌，载荷力小于0.1微米。在镍表面得到5-50 nm深的平方孔洞，但在铜和金上观察到由于剥离材料的粘结而产生的隆起。此外，在镍的情况下，划痕深度随加载力和划伤次数的增加而增加。划痕深度也强烈依赖于x方向扫描线数，而与x方向扫描速度和x-y方向扫描宽度关系不大。结果表明，纳米厚度材料的去除是可控的。微细加工的机理应由金属的塑性、粘结性和氧化物表面等因素决定。该方法对各种材料的微细加工具有很强的实用价值。

First, we constructed a scanning probe microscope (SPM) system for micromachining studies. The SPM system consists of a SPM unit, an atmosphere control apparatus and a measuring/controlling system. The SPM unit has a mechanism which can measure the lateral force images as well as the normal force images.Secondly, we studied micro-machining of pure metal surfaces in air by the SPM that has a very sharp diamond tip mounted on the end of a cantilever beam. Samples of pure metals, such as Ni, Cu and Au, were prepared by vapor deposition or mechanical polishing of bulk metals. Sample surfaces were scratched with x-y-scanning of 0.5-3 mu m x-direction width and 0.5-20 mu N loading force, and topographies of the scratched area were observed by the same SPM with a loading force of less than 0.1 muN.Flat square hollows of 5-50 nm depth were obtained on Ni, although the ridge caused by the adhesion of removed materials were observed on Cu and Au. In the case of Ni, moreover, the scratched depth is increased with increasing loading force and repetition numbers of scratching. The scratched depth is also strongly dependent on numbers of x direction scan line, but scarcely on x direction scan rate and x-y direction scan width. Results obtained indicate that the nano-scale thickness material removal can be controlled. The mechanism of micro-machining should be determined by several factors such as plasticity, adhesive property and oxide surface of metals. The method presented here will be powerful for micro-machining of various materials.