Fatigue and thermal fatigue testing of Pb-Sn solder joints

Conference · Thu Jan 01 04:00:00 EST 1987

OSTI ID:7071906

Frear, D; Grivas, D; McCormack, M; Tribula, D; Morris, Jr, J W

In an electronic package, materials of different thermal expansion coefficients are usually joined with Pb-Sn solder. The combination of temperature fluctuations and different thermal expansion coefficients creates a condition of thermal fatigue in the solder joints. This paper presents a discussion of experimental techniques developed to study fatigue in solder joints. Specimens have been developed to reproducibly test solder joints in shear using a modified double lap shear configuration. Tests were performed using a digital loadframe especially designed to isothermally fatigue solder joints in shear. Joints tested had a nominal solder composition of 60Sn-40Pb soldered to Cu. Failures were found to occur in the solder joint after fewer cycles at 125/sup 0/C than at lower temperatures. Solder joints were also tested in shear thermal fatigue. A specimen design consisting of two materials with different thermal expansion coefficients constraining a solder joint was cycled between -55/sup 0/C and 125/sup 0/C. Results of these tests indicate that there is a coarsening of the solder near the joint interface and fatigue cracks initiate in these coarsened regions.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 7071906
• Report Number(s): LBL-22878; CONF-870486-1; ON: DE87006938
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420800* -- Engineering-- Electronic Circuits & Devices-- (-1989)
ALLOYS
COPPER
ELECTRONIC CIRCUITS
ELEMENTS
FAILURES
FATIGUE
JOINTS
LEAD ALLOYS
MECHANICAL PROPERTIES
METALS
SHEAR
SOLDERED JOINTS
THERMAL CYCLING
THERMAL FATIGUE
TIN ALLOYS
TRANSITION ELEMENTS