Thermal cycling tests on surface-mount assemblies

Technical Report · Tue Mar 01 00:00:00 EST 1988

DOI:https://doi.org/10.2172/5023426· OSTI ID:5023426

Jennings, C W

The capability of surface-mount (SM) solder joints to withstand various thermal cycle stresses was evaluated through electrical circuit resistance changes of a test pattern and by visual examination for cracks in the solder after exposure to thermal cycling. The joints connected different electrical components, primarily leadless-chip carriers (LCCs), and printed wiring-board (PWB) pads on different laminate substrates. Laminate compositions were epoxy-glass and polyimide-glass with and without copper/Invar/copper (CIC) inner layers, polyimide-quartz, epoxy-Kevlar, and polyimide-Kevlar. The most resistant joints were between small LCCs (24 and 48 pins) and polyimide-glass laminate with CIC inner layers. Processing in joint formation was found to be an important part of joint resistant. Thermal cycling was varied with respect to both time and temperature. A few resistors, capacitors, and inductors showed opens after 500 30-min cycles between -65/degree/C and 125/degree/C. Appreciable moisture contents were measured for laminate materials, especially those of polyimide-Kevlar after equilibration in 100/percent/ relative humidity at room temperature. If not removed or reduced, moisture can cause delamination in vapor-phase soldering. 17 refs, 12 figs.,10 tabs.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5023426
• Report Number(s): SAND-87-0873; ON: DE88007695
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
SOLDERED JOINTS
PERFORMANCE TESTING
THERMAL STRESSES
ELECTRIC CONDUCTIVITY
FAILURES
THERMAL CRACKING
VOIDS
CHEMICAL REACTIONS
CRACKING
DECOMPOSITION
ELECTRICAL PROPERTIES
JOINTS
PHYSICAL PROPERTIES
PYROLYSIS
STRESSES
TESTING
THERMOCHEMICAL PROCESSES
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Equipment
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