Fabrication Of Monocrystalline Silicon Grating Mask With Small Flare Angle And Its Pattern Transfer Technology

Synchrotron radiation,as the most operated large device in the world,lights up the microcosmic world for human beings like a beacon in the dark.In synchrotron radiation,monochromator is the indispensable instrument to realize the monochromator of the beam line,and grating,as an important component of the monochromator,is the key to ensure the stable operation of the beam line.In our country,we are pushing forward the construction of synchrotron radiation,so it is urgent to shine raster in the soft X ray long wave band.It is of great significance for the localization of national synchrotron radiation devices to study the fabrication technology of small shining Angle grating suitable for soft X-ray long wave band.In this thesis,the soft X-ray long wave band of the shining grating is studied and produced in accordance with the design requirements.The main work of the project includes the following parts:1.Design for soft X-ray long band small flare Angle grating.The grating diffraction efficiency was simulated based on the strict coupled wave theory,and the grating’s parameters such as flare Angle,engraving density and groove depth were analyzed and calculated to determine the grating structure parameters corresponding to high diffraction efficiency.The structural parameters are optimized and the errors allowed in wet etching process are calculated.2.The alignment mode of mask lines and <111> crystal direction is studied.The calibration of <111> crystal direction was realized by pre-etching,which made the calibration process more convenient and accurate.The alignment accuracy of preetching crystal direction was less than 0.053°.Aiming at the preparation of high linear density grating mask,the static holographic alignment method is studied.In the alignment process,the high precision rotary table is used to realize the accurate adjustment of silicon wafer placement,and the high linear density grating mask is prepared by Moire fringe frequency doubling adjustment method,which improves the accuracy of crystal alignment.3.The anisotropic wet etching process of monocrystalline silicon is studied.The method of reducing the width of grating platform and the roughness of shining surface is explored by improving the process flow.A platform is formed at the top of the glowing grating prepared by wet etching.In order to reduce the width of the platform,exposure and development parameters are adjusted to ensure the smooth and integrity of the photoresist mask.The width ratio of the photoresist mask is reduced by the photoresist ashing process to reduce the width of the platform.By changing the ratio of etching solution and adding active agent to etching solution,the roughness of shining surface can be reduced.The grating diffraction characteristics are analyzed by fitting the grating groove function according to the measured groove function.Determine the diffraction efficiency of the grating prepared at the shining wavelength,explore the actual diffraction efficiency of the grating prepared,compare the actual value and the ideal value of the diffraction efficiency,and analyze the reasons for the reduction of the diffraction efficiency.