| 摘要 |
A method for forming a self-align insulation of a passing gate is disclosed. First, a substrate is provided. A deep trench filled with silicon material and a shallow trench isolation adjacent to the deep trench are formed in the substrate. A patterned pad oxide and a patterned hard mask are sequentially formed on the substrate. The patterned pad oxide and the patterned hard mask together define the opening of the deep trench. Then, an oxidation step is carried out to form a first oxide layer serving as the insulation of a passing gate on the top surface of the silicon material of the deep trench. Later, a first Si layer is formed to cover the first oxide layer. Afterwards, the hard mask is removed.
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