PCBA Storage: How Long Can You Keep Boards Before Assembly?
2026-06-30
You received your bare PCBs. But assembly is scheduled for next month.
How long can you store them before soldering?
The answer depends on the surface finish.
Shelf Life by Surface Finish
Finish Shelf Life Storage Condition
ENIG 12+ months Sealed, dry
HASL 6–12 months Sealed, dry
Immersion Silver 6–12 months Sealed, dry (anti-tarnish paper)
OSP 3–6 months Sealed, dry, cool
Immersion Tin 3–6 months Sealed, dry
ENIG 12+ months Sealed, dry
HASL 6–12 months Sealed, dry
Immersion Silver 6–12 months Sealed, dry (anti-tarnish paper)
OSP 3–6 months Sealed, dry, cool
Immersion Tin 3–6 months Sealed, dry
Why Shelf Life Matters
- OSP oxidizes over time – solder won't wet properly
- Immersion Silver tarnishes – causes poor solder joints
- Immersion Tin grows whiskers – creates shorts
Storage Best Practices
Requirement Specification
Temperature 20–25°C
Humidity < 60% RH
Packaging Vacuum-sealed with desiccant
Handling Gloves only – no bare hands
Temperature 20–25°C
Humidity < 60% RH
Packaging Vacuum-sealed with desiccant
Handling Gloves only – no bare hands
What STG Electronic Does
- Vacuum sealing – Standard for all finished boards
- Humidity indicators – Included in every package
- Re-baking – Available for boards that exceed shelf life
Common Mistake
Opening the vacuum bag and storing boards uncovered.
Result: Moisture absorption. Board warps during reflow.
Ready to Store Your Boards Right?
PCBA Functional Testing: Why Powering On Your Board Is Not Enough
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