Power or pin checks report missing or wrong routing tracks. How do you proceed?
From PDVerse PnR Interview Handbook · pdVerse Mentor Guide
Short Answer
Confirm technology-layer definitions, preferred directions, pitch, offset, width, core coverage, restrictions, and whether tracks were intentionally regenerated. Do not create arbitrary tracks to silence the check.
Technical Explanation
Tracks are technology-dependent routing opportunities, not decorative grid lines. The dp_pre_power_insertion and dp_pre_pin_placement groups depend on valid routing directions and tracks. Compare against the approved technology setup.
Formula Or Decision Rule
Decision rule: required layers have approved track patterns crossing the intended regions.
What To Check
• Warning sign: A locally invented pattern fixes one pin but conflicts with spacing or the rest of the block. • Inspect: choose one affected region, macro, row, pin, path, or net and trace the physical cause. • Correct: Restore the approved track definition and rerun power, pin, and floorplan reports.
Command Checks & Actions
• create_track -layer <layer> -space <pitch> -coord <offset> -width <width> -dir <X_or_Y>: creates a routing-track pattern
• check_design -checks {dp_pre_power_insertion dp_pre_pin_placement}: runs named design-planning check groups
Run only the commands needed for this question. Save the report with the floorplan version and analysis context.Healthy, Suspicious & Hard-stop Results
• Healthy: Confirm technology-layer definitions, preferred directions, pitch, offset, width, core coverage, restrictions, and whether tracks were intentionally regenerated. Do not create arbitrary tracks to silence the check. • Suspicious: A locally invented pattern fixes one pin but conflicts with spacing or the rest of the block. • Hard stop: required legality or physical feasibility is missing or unexplained. Restore the approved track definition and rerun power, pin, and floorplan reports.
Common Mistake
Do not hide the symptom with an arbitrary utilisation, halo, channel, blockage, pin move, or die-size change. A locally invented pattern fixes one pin but conflicts with spacing or the rest of the block.
What The Interviewer Is Testing
The interviewer is testing whether you can connect “Power or pin checks report missing or wrong routing tracks. How do you proceed?” to measurable physical evidence and an owned correction.
Follow-up Question & Model Response
Follow-up probe: What would make you change your decision? Model response: “I would change it if the same controlled rerun shows that a locally invented pattern fixes one pin but conflicts with spacing or the rest of the block. I would use the named objects and reports to decide whether to iterate, waive, or return the issue.”
Practical Example
Symptom: A locally invented pattern fixes one pin but conflicts with spacing or the rest of the block. Corrective path: Restore the approved track definition and rerun power, pin, and floorplan reports.
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