A method for improving the coating capability of low dielectric layer is disclosed. The method includes steps of an etching stop layer is deposited a semiconductor substrate, an adhesion promoter layer is spun-on the etching stop layer. The pre-wetting process being performed on the adhesion promoter layer to enhance the coating capability of the low-k dielectric layer, and thus improve the coating quality through the pre-wetting process of baked adhesion promoter layer before the low-k dielectric layer is applied.