Assembly yield is the percentage of die surviving the packaging process — measuring quality of die attach, wire bonding, molding, and other assembly steps, typically 98-99.5%, with failures indicating handling damage, process issues, or equipment problems.

What Is Assembly Yield?

• Definition: (Good packages / Die input) × 100%.
• Typical: 98-99.5% for mature processes.
• Measurement: From die input to packaged device output.
• Impact: Determines packaging cost per good unit.

Why Assembly Yield Matters

• Cost: Low yield wastes expensive die and packaging materials.
• Throughput: Yield loss reduces effective capacity.
• Quality: Assembly defects can cause field failures.
• Process Control: Yield trends indicate equipment health.

Failure Modes

• Die Attach: Voids, delamination, cracking.
• Wire Bonding: Broken wires, poor bonds, shorts.
• Molding: Voids, wire sweep, package cracks.
• Handling: Die breakage, contamination, ESD.

Improvement: Focus on equipment maintenance, process optimization, and handling procedures to maximize assembly yield.

Assembly yield is the packaging efficiency metric — high yield means reliable, cost-effective packaging that preserves the value of expensive die.