Title :
Handling of highly-moisture sensitive components-an analysis of low-humidity containment and baking schedules
Author :
Shook, Richard L. ; Goodelle, Jason P.
Author_Institution :
Lucent Technol., AT&T Bell Labs., Allentown, PA, USA
fDate :
4/1/2000 12:00:00 AM
Abstract :
Unique component handling issues can arise when an assembly factory uses highly-moisture sensitive surface mount devices (SMDs). This work describes how the distribution of moisture within the molded plastic body of a SMD is an important variable for survivability. JEDEC/IPC moisture level rated packages classified as Levels 4-5a are shown to require additional handling constraints beyond the typical out-of-bag exposure time tracking. Nitrogen or desiccated cabinet containment is shown as a safe and effective means for long-term storage provided the effects of prior out-of-bag exposure conditions are taken into account. Moisture diffusion analyzes coupled with experimental verification studies show that time in storage is as important a variable as floor-life exposure for highly-moisture sensitive devices. Improvements in floor-life survivability can be obtained by a handling procedure that includes cyclic storage in low humidity containment. SMDs that have exceeded their floor-life limits are analyzed for proper baking schedules. Optimized baking schedules can be adopted depending on a knowledge of the exposure conditions and the moisture sensitivity level of the device
Keywords :
integrated circuit packaging; materials handling; moisture; plastic packaging; surface mount technology; JEDEC/IPC moisture level rated packages; baking schedules; cyclic storage; desiccated cabinet containment; floor-life survivability; highly-moisture sensitive components; long-term storage; low humidity containment; low-humidity containment; molded plastic body; prior out-of-bag exposure conditions; surface mount devices; survivability; Additives; Assembly; Circuits; Electronics packaging; Humidity; Moisture; Nitrogen; Plastics; Production facilities; Temperature sensors;
Journal_Title :
Electronics Packaging Manufacturing, IEEE Transactions on
DOI :
10.1109/6104.846930