摘要 |
A method for an isolation structure is provided. First, a substrate with a shallow trench isolation is provided. Second, a patterned mask is formed on the substrate. Then, the substrate is etched using the patterned mask to respectively form a first deep trench and a second deep trench as well as a first undercut and a second undercut on opposite sides of the shallow trench isolation. Later, the first deep trench and the second deep trench are partially filled with Si. Afterwards, the first deep trench and the second deep trench are filled with an isolation material to form the isolation structure.
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