Method for improving thickness uniformity of grid side wall spacing layer

The invention discloses a method for improving the thickness uniformity of a grid side wall spacing layer. The method comprises the step of providing a semiconductor silicon wafer with a grid structure. A reaction period comprises the steps of introducing a precursor special gas into the surface of the silicon wafer to be adsorbed until saturation, introducing a cleaning gas, introducing a reaction special gas so as to be reacted with the absorbed precursor special gas at the surface of the silicon wafer, and introducing the cleaning gas again; and the reaction period is repeated until required thickness of SiO2 for spacing is deposited. According to the invention, atomic layer vapor deposition process of a furnace tube is adopted to prepare the grid side wall spacing layer, a traditional tetraethyl orthosilicate (TEOS) process or high-temperature thermal oxidation (HTO) process is replaced in grid side wall spacing layer preparation, thereby improving the step coverage rate and the thickness uniformity of th