| 摘要 |
PURPOSE: A method of forming a capacitor of a ferroelectric RAM(Random Access Memory) device is provided to simplify forming processes by performing one-time etching using a hard mask of a stack structure. CONSTITUTION: A lower electrode layer(4) made of Pt or Ir, a ferroelectric film(5) made of SBT or BLT, and an upper electrode layer(6) made of Pt or Ir are sequentially formed on a semiconductor substrate(1) with a predetermined structure. A hard mask for defining a capacitor region is formed thereon. The hard mask is composed of a first TiN layer(7), a polysilicon layer(8), and a second TiN layer(9). A capacitor is formed by performing one-time etching on the upper electrode layer, the ferroelectric film and the lower electrode layer using the hard mask. At this time, a first mixed gas of O2 and Cl2 is used for etching the upper and lower electrode layers and a second mixed gas of Ar and CF4 is used for etching the ferroelectric film.
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