Process improvement of high aspect ratio nano-gratings based on synchrotron x-ray

To achieve better structural accuracy and aspect ratio, nano-gratings with a vertical angle close to 90 degrees and a depth-to-width ratio of about 8 were prepared by synchrotron radiation. The optimal exposure dose and development time were determined to be 0.006 (A center dot h) and 6 min, respectively, by observing the surface loss and roughness of the gratings with slit widths of 150 nm and 250 nm under different conditions. To obtain the desired rectangular grating structure, the experimental conditions were optimized with the help of controlled variables experimental method. With the mask-to-photoresist pitch and the development and drying temperatures of 20 mu m and 23 degrees C, the optimized depth-to-width ratio of the nano-gratings with a slit width of 250 nm can reach 8.28. The cone angle can reach 88.4 degrees. The aspect ratio of the nano-gratings with a slit width of 150 nm is 7.18, and its cone angle is 87.1 degrees.

Automated summary

Nano-gratings with high structural accuracy and aspect ratio were prepared using synchrotron radiation by optimizing the experimental conditions. The optimal exposure dose and development time were determined by observing surface loss and roughness. The controlled variables experimental method helped achieve the desired rectangular grating structure.