Method for manufacturing semiconductor structure and capable of controlling thicknesses of dielectric layers

A method for manufacturing a semiconductor structure includes forming a first dielectric layer on a substrate; forming a second dielectric layer on the first dielectric layer; using a photomask to apply a photoresist to cover a first part of the second dielectric layer; removing a second part of the second dielectric layer while retaining the first part of the second dielectric layer; and removing the photoresist. The first part of the second dielectric layer covers a first part of the first dielectric layer in a first area. The second part of the second dielectric layer covers a second part of the first dielectric layer in a second area. The first area is corresponding to a memory device. The second area is corresponding to a logic device.