The excellent jet energy resolution required for precise physics measurements at ILC is achievable using a Particle Flow Method and highly granular calorimeters. As it was shown by CALICE international R&D collaboration, the silicon-tungsten imaging electromagnetic calorimeter provides the best granularity, stability and resolution of jet energy measurement. After proving the calorimeter concept with physical prototypes in 2005–2011, an emphasis is now moved to building a technological prototype satisfying challenging requirements. All chosen technologies should be reliable and scalable for a mass production of a future detector. We report on the current status of R&D, in particular, on beam and charge injection tests of the technological prototype and on the tests of ECAL mechanical structure. We also report on our plans to build a realistic prototype detector and test it together with an existing carbon fiber-tungsten mechanical structure. A similar silicon-tungsten calorimeter technology has been recently proposed for the Phase 2 upgrade of CMS end-cap calorimeter and future high energy circular collider projects.