| 摘要 |
PURPOSE: A method for forming a trench capacitor is provided to prevent a parasitic transistor by forming a multi-layered sidewall spacer of a transistor capacitor. CONSTITUTION: A method for forming a trench capacitor comprises the steps of: forming a hard mask composed of an oxidation layer and a nitride layer, on a silicon substrate; forming a trench on the silicon substrate by the hard mask; forming an external electrode of the trench capacitor on the silicon substrate exposed by the trench; forming a capacitor insulation layer on an inner wall of the trench having the external electrode; forming a first internal electrode by burying conductive material inside the trench including the capacitor insulation layer; eliminating the first internal electrode to a predetermined depth from the surface of the silicon substrate; forming a multi-layered sidewall spacer composed of the capacitor and the nitride layer, by forming a nitride layer on a capacitor nitride layer formed on a sidewall of the trench; eliminating a upper part of the sidewall spacer; forming a strap on a silicon substrate exposed by the elimination of the sidewall spacer; forming a second internal electrode by filling up the portion again in which the first internal electrode is eliminated, with conductive material; patterning the second internal electrode to a depth lower than the surface of the silicon substrate; and eliminating a part of the second internal electrode and a side of the strap in the vertical downward direction, and forming an isolation layer in the eliminated portion.
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