Semiconductor Data

The testing of semiconductor devices by automated test systems produces a very large amount of different types of data.  In general the data can be classified a parametric or categorical measurement.  Parametric measurements consist of numerical values of voltage, current, resistance, and frequency of operation to name a few.  Catagorical measurements classify data into categories or "bins" instead of numerical values.

 A parametric measurement can be described by a name, value, and associated limits and units.  Categorical measurements can be described by a type, name, and value.  Additionally, attributes for data on wafers such as wafer size, die size help to classify the data for analytics.  A generalized data model can be created from the measurements and thier attributes.  The original proprietary data model for semiconductor data was introduced by Teradyne in 1985 and named the "Standard Test Data Format" (STDF).  SEMI’s Collaborative Alliance for Semiconductor Test (CAST) RITdb group is working on a more modern standard to succeed STDF that is also a complete environment for semiconductor test and manufacturing.  No doubt that RITdb will be successful but adoption will require significant assimilation, conversion, and cost to implement.  However, A simpler and more generic file based data model is often better for smaller cases.