Calibre YieldAnalyzer tool uses a collection of fab- and process-related defect distribution statistics to analyze and predict the Defect Limited Yield (DLY) of semiconductor ICs. It provides yield-awareness and visibility into future manufacturing problems before the IC is manufactured.
Although the contents of the defect density files vary from foundry to foundry, they all tend to cover at least the following in one way or another: defect-density distribution information for each defect type of every layer in a given process technology.
Since fab- and process-related defect statistics are highly sensitive and contain confidential information it is available only in encrypted form.
A DDK is the TSMC DFM Data Kit that they supply in order to support the Critical Area Analysis application in such tools as Calibre YieldAnalyzer. This kit is a proprietary encrypted format from TSMC that provides defect densities and failure rates for these applications.
Other foundries provide similar defect statistics data in their own proprietary formats (for example UMC) or in the MG format.