STUDY OF A LITHOGRAPHY TECHNIQUE WITH LOW COST BY NANO-HEAT SPOT

在这个项目中，我们专注于纳米尺度加热的现象。的制造技术（这里称为热光刻）的发展和超分辨率读出机制的阐明进行。聚焦激光光斑内的光强具有高斯分布，由其引起的温度分布也具有类似的分布。因此，可以在聚焦的激光光斑的中心产生具有亚波长尺寸的高温区域。由加热引起的物理或化学反应可以被限制在这个区域内。这种现象对于制造纳米尺度结构是有用的，并且与超分辨率读出机制整体相关。用TbFeCo和ZnS-SiO_2组成的样品成功地制备出直径为50 nm、间距为50 nm的微小点。这些尺寸和间距约为光学衍射极限的六分之一。此外，先进的碳纳米管（CNT）探针的详细观察制造的结构。与传统的CNT探针相比，采用具有钝顶点的基底探针并将CNT长度设置为约200 nm导致更好的耐久性和更低的噪声。超分辨率读出的机制被认为与光学近场或表面等离子体有关，然而，从本研究中可以清楚地看出，纳米尺度的加热在该机制中起着重要作用，并且阐明了器件结构中各层的作用。这些结果导致了超分辨率光盘发展的突破。未来，将开展热光刻在半导体制造中的应用，以及进一步阐明超分辨率读出机制和开发温度测量系统。

In this project, we focused on the phenomenon of nano-scale heating. The development of a fabrication technique (referred to here as thermal lithography) and the elucidation of the super-resolution readout mechanism were carried out. Light intensity inside a focused laser spot has a Gaussian profile and the temperature distribution induced by it has also a similar profile. Therefore, a high temperature area with sub-wavelength dimensions can be generated in the center of the focused laser spot. Physical or chemical reactions induced by heating can be confined inside this region. This phenomenon is useful for fabricating nano-scale structures and is integrally related to the super-resolution readout mechanism. We succeeded in producing minute dots 50 nm in diameter and with a spacing of 50 nm using a sample consisting of TbFeCo and ZnS-SiO_2. These dimensions and spacing were approximately one sixth of the optical diffraction limit. Additionally, advanced carbon nano tube(CNT) probes were developed for the observation of the fabricated structures in detail. The adoption of a base probe with a blunt apex and setting the CNT length to approximately 200 nm lead to better durability and lower noise in comparison with conventional CNT probes. The mechanism of super-resolution readout was believed to be related to the optical near-field or surface plasmons, however, it is clear from this study that nano-scale heating plays an important role in the mechanism, and the role of the each layer within the device structure was clarified. These results lead to a breakthrough in the development of super-resolution optical disks. In the future, application of thermal lithography to semiconductor fabrication as well as further clarifying the super-resolution readout mechanism and developing a temperature measurement system will be carried out.