The Hidden Threat in Analog IC Migration: Why Electromigration rules can make or break your next tapeout

By Thalia

September 16, 2025

When we talk about analog IC migration challenges, the conversation usually centers on device modelling, parasitic extraction, or layout density rules.  But there’s an equally important aspect that can turn a successful design into a reliability nightmare: electromigration violations.

Analog IC migration isn’t just about device models, parasitics, or layout rules. There’s another silent killer: electromigration (EM) violations.

Too many teams discover EM issues after fabrication—sometimes months later, when field failures start rolling in.  The financial hit hurts, but the reputation damage?  That’s what keeps engineering managers awake at night.

The engineering reality: why EM hits analog harder

Electromigration—the gradual movement of metal ions due to electrons colliding owing to high current density—isn’t just a textbook reliability concern.  In analog designs, it’s a ticking time bomb with unique characteristics:

Steady-state current profiles: Unlike digital circuits with switching currents that average out over time, analog bias networks, current mirrors and reference paths carry continuous DC currents.  These steady currents create sustained EM stress that digital EM analysis tools might underestimate.

Precision sensitivity: A 1% resistance change from EM-induced voiding and hillocks might be negligible in digital logic, but it can destroy the matching in a differential pair or shift a bandgap reference out of specification.

Layout constraints: Analog layouts prioritize symmetry and matching.  When EM violations force you to widen metal traces, maintaining these critical geometric relationships becomes exponentially harder.

The migration multiplier effect

Here’s where migration amplifies the EM challenge.  Every foundry defines different current density limits based on their metal stack characteristics:

• Process-specific limits: for instance, a 22nm node might allow 2mA/μm on M1, while 16nm restricts it to 1.5mA/μm
• Metal stack variations: Thinner lower metals, different via structures, varying thermal properties
• Temperature derating: New processes may have more aggressive temperature coefficients

The result?  A power bus that was perfectly sized for your 65nm process violates EM rules at 28nm. And unlike digital designs where automated place-and-route tools can adjust routing on-the-fly, analog layouts require manual intervention that can take weeks.

The current state of EM analysis: Verification without solutions

Most teams rely on commercial EM verification tools like Calibre® PERC™ or Voltus™.  These tools excel at identifying violations but stop there.  They’ll report which traces exceed current density limits, but they won’t provide guidance on how to fix violations while preserving critical analog constraints like device matching or layout symmetry.

This gap between detection and correction is where migration projects get stuck.  Engineers end up in manual rework cycles, iteratively adjusting metal widths, re-running extraction, checking timing, verifying EM compliance and hoping they haven’t broken something else in the process.

A different approach: EM-aware migration from day one

The fundamental issue is treating EM analysis as a post-layout verification step rather than integrating it into the migration flow itself.  What if the migration process could automatically:

1. Identify current-critical devices during the initial schematic analysis
2. Calculate required metal widths based on target process EM rules before layout begins
3. Flag layout constraints that need preservation during metal resizing
4. Suggest optimization strategies that maintain analog performance requirements

This isn’t just wishful thinking—it’s engineering pragmatism.  By front-loading EM considerations into the migration planning phase, teams can avoid the expensive discover-and-fix cycles that plague traditional flows.

Real-world impact: Beyond the DRC report

Consider a recent migration scenario: a precision ADC design moving from 180nm to 65nm. The original bias network used 10μm metal traces for the main current paths. The 65nm EM rules required 16μm minimum width for the same current levels.

Traditional approach: Layout complete, run EM check, discover 47 violations, spend three weeks manually resizing traces while fighting to maintain matching requirements.

EM-aware approach: Identify the bias network as high-risk during schematic analysis, calculate required trace widths before layout starts, plan the floor plan to accommodate wider traces, complete layout with zero EM violations.

The time savings alone justified the effort, but the real value was the confidence that the migrated design would meet reliability targets without field surprises.

The path forward

The analog migration landscape is evolving toward more intelligent, automated flows. Tools like AMALIA bridge the gap between EM analysis and actionable design guidance, helping teams identify high-risk areas early and optimize their approach before costly rework cycles begin.

The question isn’t whether your next migration will face EM challenges—it’s whether you’ll discover them during design or after production.  For analog designs where precision and reliability are non-negotiable, EM-aware migration isn’t just a nice-to-have feature. It’s a competitive necessity.

What EM challenges have you encountered in your migration projects? The analog design community learns best when we share real-world experiences and solutions.