Synopsys recently worked with the members of the Interconnect Modeling Technical Advisory Board (IMTAB) of the IEEE Industry Standards and Technology Organization (IEEE-ISTO). The collaboration has resulted in a parasitic variation modeling solution to address the effects of double patterning technology (DPT), targeted for use in 20-nanometer (nm) IC manufacturing.
While working with IMTAB and leading foundries, Synopsys developed a novel modeling technique that eliminates the need to insert the time-consuming coloring step during the implementation and signoff flow, with negligible impact on extraction runtime. The new DPT model extensions will be available to the EDA and semiconductor industries through the open source licensed Interconnect Technology Format (ITF) version 2012.06 ratified by IMTAB members. The ITF format can be licensed for no charge through Synopsys’ Technology Access Program (TAP-in(SM)).
DPT is a critical technique for ensuring printability of device and interconnect layers in 20-nm IC manufacturing. However, splitting layers into two masks can introduce timing variations as a consequence of mask misalignment in the manufacturing process. To enable successful 20-nm design tapeouts and manufacturing, the IMTAB members determined that a DPT-aware modeling solution for parasitic extraction was needed to account for the timing impact and address it in the physical implementation and signoff design flow.
In addition to DPT modeling, IMTAB has also approved enhanced trench contact device modeling extensions in the ITF to include evolving 20-nm characteristics. The trench contacts are used for local device interconnections that improve density and lower resistance. However, additional challenges are introduced in modeling co-vertical conductors and associated large fringe capacitances. To deal with these issues, specific 20-nm extensions were added to explicitly model silicon dielectric underneath the device and the special dielectric region between the gate and raised diffusion to enable accurate modeling of the new parasitic effects.