  International Large Detector (ILD) adopts Particle Flow Algorithm (PFA) for
precise measurement of multiple jets. The electromagnetic calorimeter (ECAL) of
ILD has two candidates sensor technologies for PFA, which are pixelized silicon
sensors and scintillator-strips with silicon photomultipliers. Pixelized
silicon sensors have higher granularity for PFA, however they have an issue of
cost reduction. In contrast, scintillator-strips have an advantage of
relatively low cost and a disadvantage of degradation of position resolution by
ghost hits, which are generated by orthogonal arrangement. Hybrid ECAL using
both candidates is proposed to supplement these disadvantages. In this paper,
we report an optimization study of the hybrid ECAL using detector simulation.
