Method for forming trench isolation
A trench isolation method is disclosed. A substrate having thereon a pad layer and a hard mask is provided. An opening is formed in the hard mask. The substrate is etched through the opening to thereby form a first trench. A spacer is formed on a sidewall of the first trench. A second trench is then etched into the substrate through the first trench by using the spacer as an etching hard mask. The substrate within the second trench is then oxidized by using the spacer as an oxidation protection layer, thereby forming an oxide layer that fills the second trench. The spacer is then removed to reveal the sidewall of the first trench. A liner layer is then formed on the revealed sidewall of the first trench. A chemical vapor deposition process is then performed to deposit a dielectric layer that fills the first trench.
Anpec Electronics Corporation
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Chia-Hao Yung-Fa
Chang Lin