Question 1

What is the Timing Limit of Out-of-Bag Exposure?

Accepted Answer

The duration a moisture sensitive component spends in an ambient environment after its protective barrier has been breached dictates its remaining shelf life. During out-of-bag exposure, the plastic package of an integrated circuit absorbs water from the air at a rate determined by the local humidity. This accumulated moisture poses a risk of vapor expansion and package cracking during the high temperatures of the reflow oven. Assembly teams must track this time meticulously to ensure parts are soldered before they exceed their rated floor life.

Question 2

What is the Automated Tracking of Out-of-Bag Exposure?

Accepted Answer

Automated software systems or manual logs record the exact moment a moisture barrier bag is opened. If the total out-of-bag exposure exceeds the limit specified by the component’s moisture sensitivity level, the parts must be baked to remove the absorbed water. This baking process resets the clock but can only be performed a limited number of times before the component’s solderability is compromised. Maintaining a low humidity environment on the production floor extends the time available for assembly.

Question 3

What is the Standard Factory of Out-of-Bag Exposure?

Accepted Answer

Standard factory conditions of thirty percent relative humidity are assumed when calculating these limits. High humidity regions require more aggressive storage strategies to prevent the rapid accumulation of moisture.

Out-of-Bag Exposure

Timing Limit

Automated Tracking

Standard Factory

SMT Moisture Sensitivity Level Classifications and Floor Life Limits

Moisture Sensitivity Level Classification and Component Floor Life Tracking

Moisture Sensitive Parts Opened before the Line Was Ready

What the firm knows, published