Highly reliable packaged 64kbit ferroelectric memories with $0.8{;}mu extrm{m}$ CMOS ensuring ten-year retention and imprint at 125^{circ}C$ have been successfully developed. These superior reliabilities have resulted from steady integration schemes free from the degradation, due to layer stress and attacks of process impurities. The resent results of research and development for ferroelectric memories at Hynix Semiconductor Inc. are summarized in this invited paper.