Manufacturing method of trench isolation structure

The invention discloses a manufacturing method of a trench isolation structure. The manufacturing method comprises the following steps: forming a trench on a first surface of a wafer through photoetching and etching; filling an insulating isolation material in the groove; the first surface of the wafer is coated with photoresist, an inclination angle is formed between the residual photoresist and the first surface of the wafer through exposure and development, the angle of the inclination angle is 50-60 degrees, and the residual photoresist extends to the top surface of the insulated isolation material in the groove from the active region; performing dry etching on the insulating isolation material by taking the residual photoresist as an etching barrier layer, and forming a recess on the surface of the insulating isolation material; and removing the residual photoresist, and removing the redundant insulating isolation material outside the groove through wet etching. According to the method, the insulation is