The invention discloses an etch-back method for planarization at the position-near-interface of an interlayer dielectric (ILD), comprising: depositing or growing a thick layer of SiO2 by the chemical vapor deposition or oxidation method on a surface of a wafer; spin-coating a layer of SOG and then performing a heat treatment to obtain a relatively uniform stack structure; perform an etch-back on the SOG using a plasma etching, and stopping when approaching the position-near-interface of SiO2; performing a plasma etch-back on the remaining SOG/SiO2 structure at the position-near-interface until achieving a desired thickness. Since a two-step etching at the position-near-interface is employed, an extremely good smooth surface of the ILD is obtained. That is, a planar and tidy surface of the ILD is obtained not only in the center region, but also even at the edge of the wafer.