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QFN Solder Joint Life Improvement Innovation

IP.com Disclosure Number: IPCOM000012188D
Original Publication Date: 2003-Apr-16
Included in the Prior Art Database: 2003-Apr-16

Publishing Venue

Motorola

Related People

Authors:
Norman L. Owens

Abstract

Surface mount packages present challenges in order to obtain sufficient solder joint life for many applications. Leadless packages, such as the Quad Flat No-Lead (QFN) packages, present special challenges since there is no lead (flexible metal connection) to absorb the stress associated the co-efficient of thermal expansion (CTE) mismatches. Consequently, all the stress is conveyed directly through the solder joints, typically leading to earlier failure compared to leaded components. This innovation proposes that addition of non-electrically functional mechanical connections to relieve the stress on the electrical connections. Furthermore, by adjusting the size and location of these mechanical connections, a significant improvement in the solder joint life performance may be obtained.