| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for forming multi-recessed shallow trench isolation.SOLUTION: A photoresist layer having a first pattern is formed on a substrate, and a first STI structure having a first depth is formed by using the photoresist layer as a mask. A second photoresist layer having a second pattern is formed, and a second STI structure having a second depth is formed by using the second photoresist layer as a mask. The second photoresist layer is removed, and a third photoresist layer having a third pattern is formed to form a third STI structure. Thereafter, the substrate is flattened.SELECTED DRAWING: Figure 3b |
