| 摘要 |
PURPOSE: To solve the problem of a nitride liner treatment for causing a gap that cannot be ignored in a trench filler and to form a trench separation without any gap, by using a liner with a specific thickness. CONSTITUTION: In a substrate 10 with a pad oxide liner 20 and a pad nitride layer 30, the oxide liner 20 and the nitride layer 30 are etched by reactive ion etching and a separation trench 50 is cut out. Then, a conformal layer 32 with a nitride that is less than 5 nm in thickness is deposited, an oxide CVD layer 60 is deposited so that the separation trench 50 is filled, and the nitride layer 30 is removed by phosphoric acid. In this case, the separation trench 50 is backed by a thin liner 32 made of nitride, so that phosphoric acid penetrates downward, thus preventing a recess from being formed and preventing unnecessary and harmful gaps from being formed in a trench filler.
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