Towards a technological prototype for a high-granularity electromagnetic calorimeter for future lepton colliders

The CALICE collaboration is preparing large scale prototypes for highly granular calorimeters for detectors to be operated at a future lepton collider. Currently a prototype of a silicon-tungsten electromagnetic calorimeter SiW-ECAL will be assembled which in terms of dimensions and layout meets already most of the requirements given by the lepton collider physics programme and hence the detector design. In particular the front end electronics will be embedded into the layer structure of the calorimeter and have to fit within alveolar layers with less than 1 cm in height. In this paper the design of the prototype and the steps towards the realisation are presented. The presented technology plays also a key role in the upgrades of the LHC Experiments CMS and ATLAS.