TRENCH CAPACITOR STRUCTURE AND FABRICATION METHOD THEREOF

摘要

PURPOSE: The trench capacitor structure and a fabrication method are provided to reduce a divided serial resistance of a deep trench electrode and a serial capacitance thereof. CONSTITUTION: The trench capacitor fabrication method comprises: a first step of providing a semiconductor substrate(12) which has a trench(16) of a narrow upper region(16a) and a wide lower region(16b), an electrode surrounding the wide lower region(16b), and a node dielectric lining the trench of a part at which the electrode is disposed; a second step of filling the trench(16) with a polysilicon layer having a void in the wide lower region of the trench; a third step of making the structure from the second step be flat; a fourth step of removing the polysilicon layer in the narrow upper region(16a) to expose the void(26) in the wide lower region(16b); a fifth step of forming a refractory metal layer(30) in the narrow upper region(16a) and the wide lower region(16b); a sixth step of annealing the resultant structure to a refractory metal salicide layer(32) in the wide lower region; and a seventh step of removing the refractory metal layer in the narrow upper region and filling the trench structure with a polysilicon.