dtsong/chip-design-flow

Chip Design Flow

Purpose

Guide the end-to-end RTL-to-GDSII design flow, ensuring clean synthesizable RTL, realistic constraints, timing closure, and tape-out readiness.

Scope Constraints

Reviews RTL source, constraint files, and EDA tool reports. Does not execute EDA tools or modify design files. Does not perform physical verification (LVS/DRC) directly.

Inputs

• RTL source files or design specification
• Target technology node and foundry PDK
• Performance targets (clock frequency, area budget, power budget)
• Existing SDC constraints and floor plan, if any

Input Sanitization

No user-provided values are used in commands or file paths. All inputs are treated as read-only analysis targets.

Procedure

Progress Checklist

• [ ] Step 1: Review RTL coding style
• [ ] Step 2: Define synthesis constraints
• [ ] Step 3: Plan floor plan and power strategy
• [ ] Step 4: Guide place-and-route
• [ ] Step 5: Achieve timing closure
• [ ] Step 6: Tape-out readiness checklist

Step 1: Review RTL Coding Style

• Verify all RTL is synthesizable (no initial, #delay, force in design code).
• Check clock domain crossing (CDC) handling with proper synchronizers.
• Verify reset strategy (async vs sync, reset tree planning).
• Flag combinational loops and unintended latches.
• Confirm coding style matches foundry library expectations (e.g., no tri-state in core logic).

Step 2: Define Synthesis Constraints

• Write SDC constraints: clock definitions, generated clocks, clock groups.
• Define input/output delay constraints relative to system timing.
• Set false paths and multicycle paths with justification.
• Specify max transition, max fanout, and max capacitance.
• Define operating conditions for multi-corner multi-mode (MCMM) analysis.

Step 3: Plan Floor Plan and Power Strategy

• Define die/block area targets based on gate count estimates.
• Plan macro placement (memories, PLLs, IO pads).
• Design power grid: supply ring, power stripes, via density targets.
• Plan clock tree topology (balanced tree, mesh, hybrid).
• Define placement blockages and routing blockages.

Step 4: Guide Place-and-Route

• Set placement density targets (70-80% for timing, lower for routability).
• Configure global routing and detail routing options.
• Define metal layer usage (signal vs clock vs power).
• Check antenna rule compliance.
• Verify routing DRC clean before timing optimization.

Step 5: Achieve Timing Closure

• Run static timing analysis (STA) across all MCMM corners.
• Fix setup violations: buffer insertion, gate sizing, logic restructuring.
• Fix hold violations: delay cell insertion, useful skew adjustment.
• Verify clock skew and insertion delay targets.
• Check signal integrity: crosstalk delta delay, noise margin.

Step 6: Tape-Out Readiness Checklist

• LVS clean (layout vs schematic match).
• DRC clean (design rule compliance).
• ERC clean (electrical rule check).
• Formal equivalence check (RTL vs netlist, netlist vs layout).
• IR drop analysis within spec.
• Antenna rule compliance verified.
• Metal fill inserted and DRC re-verified.

Compaction resilience: If context was lost, re-read the Inputs section for design targets, check the Progress Checklist, then resume from the earliest incomplete step.

Output Format

| Stage | Status | Key Metrics | Issues | Action Items | |-------|--------|-------------|--------|--------------| | RTL review | ... | CDC crossings: N | ... | ... | | Synthesis | ... | Area: X um2, WNS: Y ns | ... | ... | | P&R | ... | Density: Z%, routing DRC: clean/N violations | ... | ... | | Timing | ... | Setup WNS: Y ns, Hold WNS: Z ns | ... | ... | | Tape-out | ... | LVS/DRC/ERC: clean | ... | ... |

Handoff

• Hand off to verification-methodology for post-synthesis or post-layout simulation.
• Hand off to forge/rtl-security-review if security-critical RTL needs audit.

Quality Checks

• [ ] RTL is synthesizable with no coding style violations
• [ ] CDC crossings identified and synchronized
• [ ] SDC constraints cover all clocks and inter-clock paths
• [ ] Floor plan has realistic area and power grid
• [ ] Timing closure achieved across all MCMM corners
• [ ] LVS, DRC, ERC clean
• [ ] Formal equivalence verified at each transformation stage

Evolution Notes

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