To investigate the effect of stencil thickness and reflow ambient atmosphere on the reliability of ceramic ball grid array (CBGA) assemblies, three levels of stencil thickness, 0.10, 0.15, and 0.20 mm, were used to print solder paste on printed circuit board (PCB). After the CBGA modules were placed on PCBs, the specimens were divided into two groups, and reflowed in nitrogen and compressed air separately. Properties of the six groups of assemblies, such as shear strength, bending fatigue life, thermal shock cycles, and vibration fatigue life, were tested to find out the optimum assembling process. The results show that assemblies prepared with a stencil 0.15 mm thick yield maximized performance. And the nitrogen ambient atmosphere demonstrates a remarkable effect on improving the fatigue life. Theoretical models are given to qualitatively explain the relationship between the solder joint volume and performance. This work provides a guideline on how to determine the soldering process parameters of CBGA assemblies.

Issue Section:
Papers on Reliability
Keywords:
ceramic packaging, ball grid arrays, reliability, reflow soldering, shear strength, bending, thermal shock, fatigue, vibrations
Topics:
Fatigue life, Reliability, Solder joints, Solders, Thermal shock, Ball-Grid-Array packaging, Vibration, Ceramics, Nitrogen, Cycles, Fatigue testing, Shear (Mechanics), Shear strength, Soldering
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Copyright © 2001
 by ASME
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