1results about How to "No contamination" patented technology

The application discloses a semiconductor structure and a preparation method of a double-trench isolation structure, and belongs to the field of semiconductors. A buffer layer and a hard mask are sequentially deposited on a semiconductor substrate; a hard mask pattern with two different size windows is formed through etching; a step coverage material is deposited, and only the small window is closed; a selective etching process is adopted to remove the horizontal step coverage material to open the bottom of the large window to form an etching window; the buffer layer is etched away through the etching window, and the remaining buffer layer at the large window is aligned with the hard mask pattern; the remaining step coverage material is removed to obtain the hard mask pattern; selective etching is performed with the hard mask pattern as a mask to obtain a large trench and a small trench; and after isolation material is filled, a double-trench isolation structure with two different sizes of STI is obtained. The application only adopts one photo mask to complete the preparation of the two sizes of STI, saves cost, and avoids contamination of the semiconductor substrate by photoresist.