Proceedings of IPACK'01, July 8-13, 2001, Kauai, Hawaii, USA

Mechanical Design Parameters for Enhanced Solder Ball Reliability of Flip-Chip PBGA Package Assembly

Kaushal Verma
Optoelectronic Center, 4E-132C
Agere Systems
Breiningsville, PA 18031

Seung-Bae Park
IBM Microelectronic
Hopewell Junction, NY 12533

Bongtae Han
CALCE Electronic Products and Systems Consortium
University of Maryland
College Park, MD 20742


The warpage of a flip-chip plastic ball grid package assembly is documented while cooling the assembly from the underfill curing temperature to -40o. The results reveal the effect of the constraints from the chip and the PCB on the global behavior of the substrate. The constraints produce an inflection point of the substrate at the edge of the chip. An experimentally verified 3-D non-linear FEM analysis proceeds to quantify the effect of the substrate behavior on the strains of assembly-level solder balls. The results from an extensive parametric study indicates that the CTE of substrate is the most critical design parameter for optimum solder ball reliability.

Complete article is available to CALCE Consortium Members

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