Semiconductor manufacturing systems, with several hundreds of different production steps, reentrant loops, cleanroom conditions and a job shop organization, are probably the most complex production systems and so is the manufacturing data structure. This high complexity requires precise planning, modelling and simulation to improve manufacturing transparencies and avoid planning inefficiencies. Although many modelling approaches for semiconductor production systems have been published, much less work has been conducted to define a common data model that supports the industrial complexity. This paper presents a common conceptual data model for semiconductor supply chains, developed in close collaboration by three European semiconductor manufacturers. Described semiconductor manufacturing use cases motivate the proposed conceptual data model. This model includes master entities, defining the structure of semiconductor supply chains with common definitions of key elements, and tracing entities, describing time dependent changes and events of the system. Expected benefits of the conceptual data model are also discussed.