GAP-FILL METHOD FOR TRENCH WITH HIGH ASPECT RATIO

摘要

PURPOSE: A gap-fill method for a trench with a high aspect ratio is provided to enable a gap-fill process in a trench capacitor with a high aspect ratio by performing a chemical mechanical polishing(CMP) step during a process. CONSTITUTION: The first pad insulation layer is formed on a silicon substrate(10). The first photoresist is formed on the substrate except the trench region of the first pad insulation layer. A trench is formed on the substrate without the first pad insulation layer. The first high dielectric layer and polysilicon are formed. A planarization process is performed until a part of nitride of the first pad insulation layer is left. The rest of the nitride and the oxide layer are removed. A silicon growth layer(20) is formed. A polysilicon growth layer is formed on the polysilicon and the first high dielectric layer in the trench region. The upper portion of the silicon growth layer and the polysilicon growth layer is planarized in response to the depth of a desired trench. The second pad insulation layer is formed. The second photoresist is patterned in the silicon growth layer region. The second pad insulation layer in the polysilicon growth layer region is removed. The second high dielectric layer is formed. The third photoresist is patterned in the second pad insulation layer region. The second high dielectric layer under a portion except a sidewall is removed. The second high dielectric layer is left only on the sidewall. The surface of the silicon growth layer is planarized.