How do asymmetric offsets change die dimensions?
From PDVerse PnR Interview Handbook · pdVerse Mentor Guide
Short Answer
Add the actual left and right offsets to core width, and the actual bottom and top offsets to core height. Do not double one offset unless both sides are truly equal.
Technical Explanation
Different sides can reserve different amounts of space for I/O, rings, or access. Illustrative example: a 1000 um core with 60 um left and 90 um right offsets gives a 1150 um die width.
Formula Or Decision Rule
Die W = core W + L + R; die H = core H + B + T, all in um.
What To Check
• Warning sign: A symmetric-margin shortcut conflicts with package or power-ring needs. • Inspect: choose one affected region, macro, row, pin, path, or net and trace the physical cause. • Correct: Use the four approved offsets, regenerate the boundary, and verify the reported dimensions.
Command Checks & Actions
• initialize_floorplan -control_type core -core_offset {<side_1> <side_2> <side_3> <side_4>}: creates the initial die, core, rows or site array, and tracks from declared controls
• report_design -floorplan: reports the floorplan state understood by the tool
Run only the commands needed for this question. Save the report with the floorplan version and analysis context.Healthy, Suspicious & Hard-stop Results
• Healthy: Add the actual left and right offsets to core width, and the actual bottom and top offsets to core height. Do not double one offset unless both sides are truly equal. • Suspicious: A symmetric-margin shortcut conflicts with package or power-ring needs. • Hard stop: required legality or physical feasibility is missing or unexplained. Use the four approved offsets, regenerate the boundary, and verify the reported dimensions.
Common Mistake
Do not hide the symptom with an arbitrary utilisation, halo, channel, blockage, pin move, or die-size change. A symmetric-margin shortcut conflicts with package or power-ring needs.
What The Interviewer Is Testing
The interviewer is testing whether you can connect “How do asymmetric offsets change die dimensions?” to measurable physical evidence and an owned correction.
Practical Example
Symptom: A symmetric-margin shortcut conflicts with package or power-ring needs. Corrective path: Use the four approved offsets, regenerate the boundary, and verify the reported dimensions.
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