| 摘要 |
A method for manufacturing ferroelectric thin-film which is used as a memory cell for an FRAM includes the steps of: (a) forming a lower electrode, a ferroelectric thin-film and an upper Pt electrode on a substrate in sequence; (b) forming a photoresist on the upper Pt electrode; (c) patterning the photoresist in a predetermined pattern; and (d) etching the substrate, the step (d) including the steps of installing a holder to which a predetermined DC self bias voltage is generated in a chamber of a plasma etching apparatus around which an RF coil is wound, of injecting Ar, chloric and fluoric gases of a predetermined composition ratio into the chamber, of applying a RF power of a predetermined frequency and power to the RF coil to generate an inductively coupled plasma in the chamber, and of etching down the substrate from the upper Pt electrode to the ferroelectric thin-film to a predetermined depth by the plasma of the Ar, chloric and fluoric gases using the photoresist as a mask. As a result, the etching rate of a ferroelectric thin-film and electrode is sharply increased, and particularly, the etching selectivity of the ferroelectric thin-film and electrode with respect to the photoresist is improved, so that the photoresist can be used as a mask.
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