Plasma etching of PZT capacitor using ISM plasma source for ferroelectric memory application

Abstract

Plasma etching of PZT capacitor was performed aiming at application for ferroelectric memory production. A high-density plasma etching tool (ULVAC Apios NE5200) was utilized and the high-density plasma occurrence at very low gas pressure together with good plasma uniformity were realized by using an ISM (Inductively Super Magnetron) plasma source and manipulating permanent magnets close to the plasma source. High etching rates of PZT (150nm/min), Pt (150nm/min) and IrOx (160nm/min), good uniformity (less than 5%) and fence-free, small-CD-shift profile were achieved by optimizing the etching process conditions such as gas species, gas pressure, mixing ratio and RF conditions for both plasma and substrate bias. Excellent ferroelectric performances such as high Qsw and low imprint were confirmed with array device indicating this tool and process are promising for ferroelectric memory production.

Key Words:

• Etching
• Dry Etching
• ISM Plasma Source
• PZT
• Pt
• IrOx
• FeRAM