Method for manufacturing a semiconductor device

A method for manufacturing a semiconductor device, comprising the following steps:

• providing a substrate, and forming an etching stop layer, a first dielectric layer, an auxiliary dielectric layer, and a second dielectric layer that are successively stacked from bottom to top on the substrate;
• patterning the second dielectric layer by using a photoresist layer as an etching blocking layer, forming a first opening pattern extending downward from an upper surface of the second dielectric layer, wherein a bottom of the first opening pattern is provided with a second opening pattern exposing a part of the auxiliary dielectric layer;
• removing the auxiliary dielectric layer based on the second opening pattern by using the photoresist layer and the remaining second dielectric layer on the bottom of the first opening pattern as an etching blocking layer, and exposing the first dielectric layer at a bottom of the second opening pattern;
• removing the first dielectric layer and the second dielectric layer based on the first opening pattern and the second opening pattern by continually using the photoresist layer as an etching blocking layer, until the auxiliary dielectric layer is exposed at the bottom of the first opening pattern;
• removing the auxiliary dielectric layer at the bottom of the first opening pattern;
• and
• removing the first dielectric layer by continually using the photoresist layer as an etching blocking layer, forming, based on the first opening pattern, a first trench extending through the second dielectric layer and the auxiliary dielectric layer and extending to the first dielectric layer, and forming, based on the second opening pattern, a second trench extending from the bottom of the first trench through the first dielectric layer and extending to the etching stop layer;
• and
• removing the photoresist layer and the etching stop layer at the bottom of the second trench, and forming a conductive layer in the first trench and the second trench.