The chip database (CDB) and the hierarchical chip database (HCDB) and their uses in a wafer representation server are described. The server provides data types and methods for hierarchically representing the three-dimensional geometry and fields of a semiconductor wafer during process, device, and yield simulation. The basic database data types and the general attribute mechanism have been used to create database extensions. These extensions implement operations frequently used by process and device simulation models. The combination of the databases and extensions forms a CDB/HCDG server that greatly reduces the effort required to create new statistical process, device, and yield simulation models. Examples of using the server to implement new models are described. Performance data demonstrate that the server is fast enough for use by analytical models during statistical simulation of macrocells, and is able to meet the representation needs of numerical simulation.>