McDry IC Package Storage Specified by IPC/JEDEC

Recommendations for IC Package Storage after Opening Moisture-Barrier Bags

As specified by IPC/JEDEC Standard 033D

	Storage Method	Workability and Cost	Result
1	Use before floor life ends	The floor life differs according to each IC package. Once an MBB has been opened, it is difficult to use leftover components for the next mounting process before the floor life ends.	Insufficient
2	Storage in dry box	When IC packages are stored in a dry box at 5%RH or lower, the floor life is indefinite permitting storage and use of a quantity of components as needed. Just-in-time mounting is possible. Unlike repacking and baking, management of man-hours is unnecessary and substantial reduction in costs is possible. The floor life can be reset in a dry box(10%RH or under). (MS Level 2-3: Resetting possible when the exposure time is within 12 hours.) The floor life can be reset in a dry box(5%RH or under). (MS Level 4-5,5a: Resetting possible when the exposure time is within 8 hours.) It is possible to store tape reels that are vulnerable to heat and cannot be baked. IC packages can be placed in a dry box temporarily when trouble occurs during mounting operation.	Optimal storage and easy operation
3	Repacking	There is a time limit to repacking. For example, NEC Electronics has set 168 hours as the allowable time after repacking for storage of MSDs. It takes time to check moisture-barrier bags for damage and holes as well as to replace desiccants with fresh ones. Only 60 minutes are available to reseal after moisture-barrier bags are opened so quick operation is necessary. Resealing performance may not be completely reliable.	Time consuming
4	Baking	IC packages that have exceeded their floor life must be baked in time for mounting which is a troublesome process. Baking oxidizes pins deteriorating wettability of solder. It is a requirement to put baked IC packages on a heat-resistant tray and displacement or pin bending may result. Tape reels cannot be baked.	Process heavy