Groove filling method

The invention discloses a groove filling method. The width of a groove is above 1 mu m and the depth of the groove is above 3 mu m. The method comprises the following steps: step 1, using TEOS as a raw material to deposit a layer of SiO2 on the surface of a silicon slice with a groove by an LPCVD process; step 2, using TEOS and O3 as raw materials to deposit a layer of SiO2 again on the surface of the silicon slice by an APCVD or SACVD process; and step 3, using TEOS and O2 as raw materials to deposit a layer of SiO2 again on the surface of the silicon slice by the PECVD process. After the groove is filled according to the method of the invention, fillers in the groove are of a multilayer film structure; and the multilayer film structure is not cracked in a subsequent high-temperature furnace annealing process.