| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a ferroelectric memory device which hardly has degradation in remanence polarity characteristic, even if a metal wiring is formed near a ferroelectric capacitor. SOLUTION: A perovskite system oxide, which is a ferroelectric material 4, is interposed between an upper electrode 5 and a lower electrode 3, to form a ferroelectric capacitor 9. Using a remanence polarity characteristic of the capacitor 9, a ferroelectric memory device 10 is manufactured. In this case, when forming a metal wiring 7 having a large coefficient of thermal expansion such as an Al wiring on the upper electrode, the material of the metal wiring 7 is heated to a temperature exceeding the Curie temperature of the ferroelectric material 4 to form the metal wiring 7. Thereby, while the temperature decreases, the tensile stress applied to a capacitor 6 from the wiring 7 is reduced at the Curie temperature, and thereby the degradation of a polarization characteristic of the ferroelectric material 4 is suppressed. The same result would be obtained if a wiring is formed with a material, which is fluidized at a temperature higher than the Curie temperature of the ferroelectric material 4, and thereafter the wiring is heated upto a fluidization temperature of the material of the wiring. Interposing a barrier film 8 between the upper electrode and the metal wiring 7 can also relax the influence of thermal expansion of the wiring.
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