Research on Pick-Place Shape Forming Technique -Construction of ultra-micro 3D structure by heaping up micro particles-

本研究的目的是建立一种机械微加工技术--拾取式成形技术，即在扫描电子显微镜下由微操作手将微小颗粒堆积起来的一种加工方法。(1)微小颗粒粘着检测方法的建立：通过构建的微力测量系统进行系统的实验，发现作用在微小颗粒上的粘附力是静电力，并且受到充电电位、表面粗糙度以及工具与物体的接触面积的影响。此外，我们还发现，由于粘弹性变形，聚合物微粒放置在基材上后，其附着力随着时间的推移而增加。基于上述发现，建立了拾取和放置微粒的技术。拾取是通过滑动颗粒来初始化粘附力来实现的。通过改变工具面对粒子的面积进行放置。(2)拾取放置成形系统的集成：集成了微操作器、扫描电子显微镜和实时图像处理器，建立了通过监测粒子运动来自动拾取粒子的技术。(3)对构建的拾取放置成形技术进行了评估：采用拾取放置成形方法，将直径为2微米的微球堆积在一起，制备出光子晶体。通过对可见光衍射图的观察和红外反射光谱的测量，发现它们的多次散射特性与理论预测基本一致。这是第一批在光学领域制造的3D光子晶体。这显然证明了拾放成形技术的有效性。

The aim of this research is to establish the pick-and-place shape forming technique, which is a fabrication mathod to heap up micro particles by a micro manipulator under a scanning electron microscope, as a mechanical micro machining technique.(1)Establishment of adhesion and detechment method of micro particles : Through Systematic experiments by constructed micro force measurement system, the adhesive force acting on micro particles turned out to be the electrostatic force and to be affected by charging potential, surface roughness, and the facing area of the tool and the object. Moreover, we found that the adhesion force of polymer micro particles increases with the passage of time after the particle is placed on the substrate as a result of viscoelastic deformation. On the basis of the above findings, techniques to pick up and place the micro particles were established. Picking-up is realized by initializing the adhesive force through sliding the particle. Placing is executed by changing the facing area of the tool against the particle.(2)Integration of the pick-and-place shape forming system : A micro manipulator, a scanning electron microscope, and a rel-time image processor were integrated and a technique to automatically pick up particles by monitoring their motion was established.(3)Evaluation of the constructed pick-and-place shape forming technique : Photonic crystals were fabricated by pick-and-place shace forming method by heaping up micro spheres of 2 mum in diameter. Through the observation of the diffraction patterns of visible light wave and the measurement of the infrared reflection spectra, we found that their multiple scattering characteristics roughly agree with the theoretical prediction. These are the first fabricated 3D photonic crystals in the optical region. This obviously proves the effectiveness of the pick-and-place shape forming technique.