A formation method of a semiconductor structure is disclosed. The method comprises the following steps of providing a surface possessing a grid film substrate, wherein a grid pattern film including a hard mask layer material layer and a silicon material layer covers a grid film surface; forming a pattern layer on a grid pattern film surface; taking the pattern layer as a mask layer and etching a part of the grid pattern film to form a grid pattern layer, wherein the grid pattern layer comprises a hard mask layer and a silicon layer located on a hard mask layer surface; and a sidewall surface of the silicon layer, which is vertical to a first direction, possesses first line width roughness; carrying out repairing etching processing on the silicon layer sidewall vertical to the first direction so that the silicon layer sidewall surface possesses second line width roughness less than the first line width roughness; taking the grid pattern layer as the mask layer to etch a grid film and forming a grid on a substrate surface; and forming a source area and a leakage area in the substrate of two sides of a grid sidewall vertical to the first direction. By using the method, the line width roughness of the grid pattern layer is reduced so that formed grid quality is increased and electric performance of the semiconductor structure is optimized.