Fractal Technologies

1. Fractal Technologies Typical STD Cell Library Errors Fractal Technologies Confidential

2. Typical Cell Presence Errors • Obsolete Cells • Cadence DFII has many times hierarchical cells that are not used anymore. (Artefacts) • Double cell entries • Cells removed from Cadence DB still remain in other formats. (Verilog, MilkyWay, Liberty, etc...) • Missing Cells • Wrong database in cds.lib included. Hierarchical cells are missing. • Cells in the CDB do not exist in the other formats due to later added cells not all Databases are updated or an older database is delivered • Documentation many times misses a cell • Due to no formal checking method • Filler and alignment cells not consistent for the various DB’s Quality in Design Formats

3. Typical Terminals & Pins Errors • Direction of the pins does not match • Input,Output, Bidirectional • Pins are in the wrong layer • Uses busses instead of single pins Quality in Design Formats

4. Typical Label Errors • Missing labels • Simply missing • Typing errors • Uppor vs lower case errors • Labels in the wrong layer Quality in Design Formats

5. Typical Net Errors • Missing net information • Due to copy actions in the Cadence Database Net information may be lost. • Database corrupt… • Busses used instead of single pins Quality in Design Formats

6. Typical Layout vs. layout Errors • Modifications in the master Cadence Database not copied to GDSII or LEF • 45 degrees not accurately enough in LEF • Abstract not generated correctly • Shifted polygons  Quality in Design Formats

7. Typical Abutment Errors • 1 grid shift  • Missing boundary layer • Layers do not touch the outline Quality in Design Formats

8. Typical Routability Errors • Pins not on grid • Wrongly coded off-set Quality in Design Formats

9. Typical Functional Equivalence Errors • Both active PRESET and SET yield different result over the various formats • Priority definitions wrong • Mismatch between asynchronous and synchronous descriptions • Missing functional description • Short circuit detection • Cont… Quality in Design Formats

10. Typical Functional Equivalence Errors • Documentation errors • Due to missing formal checking. (Depends on human reading) pin(OA1) { direction : output ; function : "(!M2|(M1&M0))" ; pin(OA2) { direction : output ; function : "(M2|(!M1&!M0))" ; pin(Z) { direction : output ; function : "!(M1^M0)" ; .lib  Datasheet  Quality in Design Formats

11. Typical Characterization Errors • Last characterization entries all 0. • Delay decreases with increasing output load • Conditional vs non-conditional descriptions • Back-annotation errors • Conditions don’t match string based • Obsolete default conditions • Non-paired setup and hold times • Swapping of Liberty file names ff, tt, vs ss Quality in Design Formats

12. Typical CCS Characterization Errors • Cells do not have a single peak current • Current curves have a “correction current” at the tail Quality in Design Formats

13. Typical ECSM Characterization Errors • ECSM-curves have large deviations (20-300%) between ECSM and NLDM delay values Quality in Design Formats

14. Conclusions • It’s better to check the STD Cell Library before using it Quality in Design Formats