Calibre Mastering Interactive PERC P2P debugging flow for faster results closure
Summary
In this webinar, we will demo the interactive P2P debug flow to break down the results and identify the resistance bottlenecks in routing more efficiently.
Details
Q&A
Note:
1. Thank you all for the questions during the webinar! Below is the transcript of the questions and answers.
2. If more support is needed for any of the issues you are facing, please open a support case at https://support.sw.siemens.com/en-US/support-case/open
Q: I am a PV engineer at a company, and I must do PERC checks, I don't have much knowledge about analog parts. How can we proceed with it?
A: If you need assistance with the PERC flow, please feel free to submit a case in the Support Center or reach out to your local AE/Support team representative. We will be happy to answer your questions.
Q: For the LDL restart flow, there is 1mA for the testing. How can it show the whole picture of the resistance issue? Secondly, can we change the I value in the LDL restart?
A: The LDL restart flow injects a 1mA current from the source to the sink.
The resistances come from parasitic extraction. PERC distributes the current in the different branches based on these resistances and then computes CD as (I/W) for metal lines and (I/A) for vias. The current value is not important from the restart P2P debug flow perspective because the goal is to get a relative measurement for the R-contribution percentage on every polygon to debug the total P2P resistance value in detail.
However, the value of 1mA cannot be changed for the LDL restart flow. If the user wants to control the current value with the goal of CD analysis, then he/she should simply run CD instead of restarting the P2P debug flow.
Q: Can we get the video recording of this session?
A: The webinar recording and all questions with written responses will be available on the Siemens Support Center page.
Q: How to provide coordinates as input instead of Device pins for P2P Checks?
A: Using the P2P interactive coordinates flow will enable the user to run P2P between 2 coordinates of the user’s input.
Q: The CD run is taking too much time for larger designs. How to optimize run time?
A: We advise using the best practices and recommendations from the foundry to maximize the tool's benefits. For large designs, it’s strongly recommended to run MTFlex mode and ensure enough memory in the machines used. If you still need help with your run, please contact your local AE or open a support case, and we will be happy to assist you.
Q: Are the colormap and blue/red colors while debugging P2P Rcomb available with other layout editors like Virtuoso or Custom Compiler?
A: Yes, we do support RVE highlighting with other layout editors, but depending on the tool, sometimes there can be some limitations (e.g., with colors, etc.)
Q: What is rdb tab? How is it different from the error tab?
A: The rdb has the P2P error results, and the other tab has the layout topology error results.
Q: What is the current assumption in CD? Can we change that based on our application like D2D, where ESD's current requirement might be less?
A: The current is assumed to be 1mA in the LDL restart flow only. The full CD run will have a different input current based on the user input, which can be changed. Please consult the manual for more details.
Q: Why do we see cd.rdb tab in the P2P run for PERC? Do we need to fix errors in the cd.rdb as well, even if we ran only P2P?
A: The cd.rdb is generated from the P2P ldl restart flow, which runs on top of an existing P2P run. The output has cd.rdb in the database name, that’s because the flow runs CD for the selected test simulation jobs.
Q: LDL is latchup-related errors, and P2P is resistance-related. Why do we see P2P results in LDL?
A: Calibre PERC categorizes all runs on the layout under the “-ldl” switch, which stands for “Layout Driven Logic.”
Q: In which of the resources the "restart -p2p_debug" is explained in detail?
A: You can find more details in the KB: MG618950 or with the following link:
Q: If we have multiple p2p_# failing, how do we get the p2p_# and then run in batch mode?
A: You can find the test number (p2p_#) either by loading the results database (dfmdb) in RVE or from the perc.rep.p2p report. It’s also possible to run the flow in batch mode; please contact support if you want more details on how to run LDL restart in batch mode.
Q: Which method of p2p debug/run is best per accuracy?
A: Both P2P and P2P debug (ldl restart) have the same accuracy and give the same P2P results. However, the ldl restart flow has more information for better debugging.
Q: How to debug disjointed paths in P2P?
A: The disjoint paths debugging is a complicated topic as it can be caused by many reasons depending on the run and test case. It can come from either the user setup, the layout design, or the PERC rules coding.
Q: Can we use an SPF netlist from a different extraction tool?
- To follow up on my question about whether one can use any standard SPF / DSPF netlist as an input to the P2P and CD tools, if we have an SPF / DSPF netlist from a different extraction tool, how would we pass the layer information to Calibre so that it can display per-layer information?
A: No, Calibre PERC P2P/CD flow doesn’t support a different netlist extraction tool output.
Q: Which versions of Calibre support the new debugging capabilities demonstrated today? Also, do you need the new Calibre Interactive GUI (not Classic) to use the newer capabilities?
A: Starting from Calibre version 2024.2, both features are supported. The features GUI setup is supported in the new GUI.
Q: Do you need a special license for this feature?
A: PERC LDL restart Debug mode consumes Calibre PERC license. It runs as (calibre -ys -perc_ldl), so you can think it consumes the YS license, but actually, this instructs Calibre to use the PERC license and not the YS license.
Q: Are ESD resistor devices recognized in the P2P flow, or does it calculate resistance only for metals and vias?
A: Assuming you mean the intentional resistors, then yes, Calibre can recognize these resistors if they’re defined in the LVS rule deck and will take it into account when calculating the P2P resistance for the full path.
Q: What is the technology-related inputs required for PERC/P2P?
A: The inputs are layout design, Calibre PERC rules, and Calibre LVS rules. Also, you need to add Calibre xRC parasitic resistance rules.
Q: Can PERC P2P be used with any net in the design? Does the net need verification text to be checked?
A: Yes, you can provide the net name for Calibre.
PERC P2P can generally run on internal nets if it can be identified by the PERC topology rules by its connectivity to certain device types or circuit patterns.
Q: Does the current density check database have a current map of the net? If so, how can I see it?
A: Yes, the current density check has the current density map of the net.
Q: Which Calibre version are these features available?
A: Starting from the Calibre version 2024.2, both features are supported.
Q: Can you demonstrate how to write out the probe file and read it back in the next run?
A: For more details about the flow, contact your local AE/support team representative, and we will be happy to answer your questions.
Q: When restarting from p2p debug, does it re-run extraction again?
A: No, it doesn’t. It restarts after the extraction.
Q: Why does the view zoom in so far when you place the probes in the viewer?
A: There is an option to control the zooming. From the GUI “Options” tab, under the “Highlighting” section.
Q: Does PERC support metal width-dependent resistivity?
A: This depends on the setup of the PEX rules. In concept, yes, Calibre PERC can support in-die variations.
Q: Can I use p2p to check internal nets but not pads?
A: No, Calibre PERC P2P doesn’t check internal nets. If no pads are defined, it’s recommended to run full path flow.
Q: How can you create the resistance segments for debugging? Do you expect us to hack the rules from the foundry?
A: Resistance segments are generated from Calibre and can be run for more detailed debugging using Calibre PERC LDL restart flow as presented in the demo.
Q: Where is the restart rdb restored? Can it be reopened if the current RVE session is closed?
A: The database from the restart flow is saved in rbd files created in the same run directory. These files can be reopened later and standalone.
Q: Could you share some guidelines to highlight resistance segmentation? I missed some step-in videos. Thank you.
A: Users need to run the LDL restart flow to highlight resistance segments. In the output rdb file, you can highlight the colormap of the Rcontrib(%), which will highlight segments in different colors depending on their % value.
Q: Will the restart flow overwrite the previous restart flow results?
A: No, the output results from the restart flow are saved in a separate RDB file from the original P2P RDB database.