VLSI Physical Design

RTL to GDSII Physical Design Flow

Complete RTL-to-GDSII physical design expertise — from logic synthesis through floorplanning, placement, CTS, routing, and tapeout signoff. Full MCMM (Multi-Corner Multi-Mode) optimization across the entire flow for timing closure at advanced process nodes.

Complete PD Flow

RTL to GDSII — Step by Step

The complete physical design flow carried out with MCMM constraints at every stage — from RTL handoff to final GDSII tapeout.

1
Logic Synthesis

RTL is synthesized into a gate-level netlist targeting the technology library. Timing constraints (SDC), area targets, and power budgets are applied. Multi-mode constraints ensure the design meets requirements across all functional modes from the start.

  • Design Compiler
  • Genus
  • SDC Constraints
  • Liberty Libraries
  • DFT Insertion
  • Multi-Mode Synthesis
2
Floorplanning & Power Planning

Die size estimation, macro placement, IO ring planning, and power grid design. Power domain partitioning for multi-voltage designs with UPF. The power network is analyzed for IR drop across all MCMM scenarios to ensure reliable power delivery.

  • Die Planning
  • Macro Placement
  • Power Grid
  • IR Drop Analysis
  • UPF / CPF
  • Voltage Islands
  • Pin Placement
3
Placement & Optimization

Standard cells are placed with timing-driven and congestion-aware algorithms. MCMM placement optimization simultaneously targets worst-case setup (slow corner) and hold (fast corner) paths. Cell sizing, buffer insertion, and logic restructuring are performed across all scenarios.

  • Timing-Driven Placement
  • Congestion Optimization
  • Cell Sizing
  • Buffer Insertion
  • MCMM Optimization
  • Scan Chain Reorder
4
Clock Tree Synthesis (CTS)

Clock trees are built to meet skew, latency, and transition targets across all MCMM corners. Multi-source CTS for complex clock architectures. Clock tree optimization accounts for OCV (On-Chip Variation) and ensures balanced insertion delay across process corners.

  • CTS
  • Clock Skew
  • Useful Skew
  • Multi-Corner Balancing
  • OCV / AOCV
  • Clock Gating
  • NDR Rules
5
Routing & Post-Route Optimization

Global and detail routing with DRC-clean targets. Signal integrity analysis for crosstalk (SI), electromigration (EM), and antenna effects. Post-route timing optimization with MCMM ensures timing closure across all corners and modes simultaneously.

  • Global Routing
  • Detail Routing
  • SI / Crosstalk
  • EM Analysis
  • Antenna Fixing
  • MCMM Timing Closure
  • ECO
6
Static Timing Analysis (STA)

Full-chip STA across all MCMM scenarios — setup analysis at worst-case slow corners, hold analysis at best-case fast corners. CPPR, OCV/AOCV/POCV derating applied. Multi-mode analysis covers functional, test, and low-power modes simultaneously.

  • PrimeTime
  • Tempus
  • Setup & Hold
  • CPPR
  • OCV / AOCV / POCV
  • Multi-Mode STA
  • ECO Fixing
7
Physical Verification & Signoff

DRC (Design Rule Check), LVS (Layout vs. Schematic), ERC, and antenna checks. Final signoff STA with extracted parasitics (SPEF). IR drop signoff, EM signoff, and formal equivalence checking before GDSII tapeout.

  • DRC
  • LVS
  • ERC
  • Calibre / ICV
  • SPEF Extraction
  • StarRC
  • Formal Verification
  • GDSII
MCMM

Multi-Corner Multi-Mode Optimization

The entire RTL-to-GDSII flow is carried out under MCMM constraints — simultaneously optimizing across multiple PVT corners and functional modes for robust timing closure.

🌡️
Multi-Corner Analysis

Timing analysis and optimization across all PVT corners simultaneously — slow-slow (worst setup), fast-fast (worst hold), and nominal. Covers process variation, voltage droop, and temperature extremes.

  • SS/FF/TT Corners
  • Voltage Variation
  • Temperature Range
  • RC Extraction Corners
  • Cmax / Cmin
Multi-Mode Analysis

Different functional modes have different active clock domains, timing constraints, and critical paths. MCMM handles all modes concurrently — functional, test/scan, JTAG, low-power sleep/retention modes.

  • Functional Mode
  • Scan Shift/Capture
  • JTAG/MBIST
  • Sleep/Retention
  • Dynamic Voltage Scaling
🔄
MCMM Through the Flow

MCMM is not just an STA technique — it's applied at every stage. Placement considers all scenarios, CTS balances across corners, routing optimizes for all modes, and signoff verifies every combination.

  • MCMM Placement
  • MCMM CTS
  • MCMM Post-Route Opt
  • MCMM STA Signoff
  • Concurrent Optimization
📐
OCV & Derating

On-Chip Variation modeling with AOCV (Advanced OCV) and POCV (Parametric OCV) for realistic timing margins. Path-based and stage-based derating for accurate pessimism reduction at advanced nodes.

  • OCV
  • AOCV / SBOCV
  • POCV / LVF
  • CPPR
  • Pessimism Reduction
EDA Tools

Industry-Standard EDA Tools

Hands-on experience with leading EDA tools from Synopsys and Cadence for the complete RTL-to-GDSII flow.

ICC2
Place & Route
Innovus
Place & Route
Design Compiler
Logic Synthesis
Genus
Logic Synthesis
PrimeTime
Static Timing Analysis
Tempus
Static Timing Analysis
Calibre
Physical Verification
ICV
Physical Verification
StarRC
Parasitic Extraction
QRC
Parasitic Extraction
RedHawk
Power & IR Drop
Voltus
Power Analysis
Formality
Formal Verification
Conformal
Formal Verification
ICC / IC Compiler
Legacy P&R
Encounter
Legacy P&R
Expertise

Physical Design Specializations

Deep expertise across the full spectrum of VLSI physical design challenges.

Timing Closure
Setup/hold fixing, CPPR, useful skew, ECO timing
Low Power Design
UPF, DVFS, power gating, retention, level shifters
Clock Architecture
Multi-source CTS, mesh clocks, clock gating, skew scheduling
Signal Integrity
Crosstalk, noise, NDR, shielding, SI-aware routing
Power Integrity
IR drop, EM, power grid design, decap optimization
Congestion Management
Placement optimization, cell padding, routing layers, blockages
Advanced Node Challenges
Multi-patterning, FinFET, density rules, via pillars
Physical Verification
DRC, LVS, ERC, antenna, density fills
ECO & Engineering Changes
Functional ECO, timing ECO, metal-only ECO, spare cells

Let's Work Together

Looking for VLSI physical design expertise? Whether it's a full RTL-to-GDSII project or specific PD challenges — let's talk.

Available for contract, consulting, and full-time roles · info@ondevtra.com