Redundant Via is a DFM (Design for Manufacturing) technique where multiple vias are placed in parallel at each via connection — providing backup current paths in case one via fails due to voiding, misalignment, or process defects.

What Is a Redundant Via?

• Standard: 1 via connecting two metal layers.
• Redundant: 2 or more vias at the same connection point.
• Impact: If one via opens, the other(s) maintain the electrical connection.
• Area Cost: Requires extra routing space — automated tools optimize placement.

Why It Matters

• Reliability: Single-via connections are the most vulnerable points in the interconnect. Redundancy provides 10-100x improvement in via reliability.
• Yield: Compensates for process defects (incomplete fill, misalignment) that affect individual vias.
• Design Rules: Many foundries strongly recommend or mandate redundant vias for production designs.

Redundant Via is the backup parachute for interconnects — ensuring that no single point of failure can break the electrical connection between metal layers.