Gratings with many types of groove profiles such as rectangles and triangles can be fabricated by wet etching silicon, during which a key step is to accurately align the grating line of the mask with the 〈111〉 orientation of silicon. Sidewall roughness can be visibly reduced by high-precision alignment, which is necessary for the fabrication of large grating structures. A fanned alignment pattern was designed and fabricated, which was then etched to accurately determine the 〈111〉 orientation of silicon. After determining the 〈111〉 orientation, a grating with a height of 48.3 μm, period of 5 μm, and area of 15 mm×15 mm was fabricated successfully by ultraviolet lithography and wet etching. The aspect ratio of the grating was approximately 20, and the roughness of the lines sidewalls was 0.404 nm. A rectangular grating with a large aspect ratio and a triangular-grooved grating were fabricated successfully with holographic lithography and wet etching. The rectangular grating was 4.8 μm tall with a period of 333 nm and an area of 50 mm×60 mm. Its aspect ratio was approximately 100 with a sidewall roughness of 0.267 nm. The period of the V-groove grating was 2.5 μm, and its sidewall roughness was 0.406 nm.