|
Track 2 Session 11
10:30 to 11:30 a.m. Thursday June 19, 2008
LCC Solder Joint Reliability in Storage
Environments and the Limitations of Modeling Mitigation Methods
With industry’s move to Surface Mount components, Leadless
Chip Carrier (LLC) castellation solder joints have become a reliability
concern, specifically in a storage environment. This session
describes a specific mitigation method and evaluates its
effectiveness through accelerated thermal cycle testing. When a
product sits in storage for 90% of its life before it is used, daily
thermal cycling, however minimal, can reduce the reliability of the LCC solder joint if there is any Coefficient of Thermal
Expansion (CTE) mismatch between the Printed Wiring Board (PWB) and the
component package material. It is becoming increasingly more
difficult to match the PWB and component CTEs because boards are
becoming more densely populated with components, components are
becoming more creatively packaged and pressure is being applied to reduce
costs. Testing results contradicted the analysis that identified
non-collapsible solder balls as the leading mitigation solution.
Non-collapsible solder balls were concluded to be less reliable than
standard castellation solder joints and therefore are an
ineffective mitigation for solder joint cracking in storage
environments.
Key Words:
Solder Joint Reliability, Accelerated Testing, Non-Collapsible,
Solder Balls, Thermal Cycling Failures, Extended Storage
Environment, Engelmeier Model, Solder Joint Model, Cracked Solder
Joints
Christa
Triebwasser and Lisa Koland
Honeywell
Coon Rapids, Minnesota |
 |
|
