Fabrication of high quality grisms for infrared observation

这项研究的目的是设计和制作高质量的用于红外光谱观测的光栅。该方法是利用硅片的各向异性刻蚀，在光刻胶表面机械地形成光栅图形，并用化学方法形成三角形的光栅槽。实验研究了(1)利用刻划引擎在光刻胶薄膜上机械成形光栅掩模图形的过程，(2)形成用于刻蚀的SiO_2光栅掩模的过程，(3)单晶硅的各向异性刻蚀过程，利用晶体取向形成预定的锯齿形沟槽轮廓。采用该标准工艺，建立了红外光栅制作的标准工艺，设计并制作了覆盖近6微米红外区的硅栅。结果表明，在栅面上形成的光栅在槽形的形状精度和各面的平整度方面均优于传统的机械刻划栅面，证明了所提出的红外栅面制作工艺的有效性。

The purpose of this research is to design and fabricate high quality grisms for infrared spectroscpopic observations. The proposed idea is to generate grating patterns mechanically onto the surface of a grism and form triangularly shaped grating grooves chemically utilizing anisotropic etching of silicon.Here, (1) the process of shaping grating mask patterns mechanically onto the photoresist thin film which is coated onto the grism surface by using a ruling engine, (2) the process of forming SiO_2 grating mask for etching, and (3) the anisotropic etching process of single crystal silicon to form pre-determined saw-tooth groove profile utilizing crystal orientation, are examined experimentally, and standard process of fabricating infra-red grisms is constructed.By adopting this standard process, a silicon grism which covers around 6mum infrared region is designed and fabricated. The grating formed on the grism surface is found to be superior to the conventional mechanically ruled gratings in the figure accuracy of the goove shape and the smoothness and flatness of each facet, and the effectiveness of the proposed process of fabricating infrared grisms is proved.