Improved yield and performance of ball-grid array packages: design and processing guidelines for uniform and nonuniform arrays

• Published in: IEEE transactions on components, packaging, and manufacturing technology. Part B, Advanced packaging Vol. 19; no. 2; pp. 310 - 319
• Main Authors: Heinrich, S.M., Shakya, S., Wang, Y., Lee, P.S., Schroeder, S.A.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.05.1996; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Capacitive sensors; Electronics; Exact sciences and technology; Fatigue; Geometry; Life estimation; Packaging; Predictive models; Semiconductor device modeling; Shape; Soldering; Solid modeling; Testing, measurement, noise and reliability; Spot weld; Mechanical stress; Interconnection; Soldered joint; Theoretical study; Package; Reliability; Modeling
• ISSN: 1070-9894; 1558-3686
• DOI: 10.1109/96.496034

Two models are presented for analyzing ball-grid array (BGA) solder interconnects: (a) a model for predicting solder joint geometries after an upright or inverted reflow process and (b) a reliability model for estimating maximum shear strain and fatigue life under a global thermal mismatch load condition. The reliability model includes a newly derived closed-form expression relating the maximum shear strain in a solder joint to the load, material, and joint shape parameters. The models are used to generate design/processing guidelines that may be used to improve the yield of a BGA soldering operation and the in-service reliability of the interconnect. Potential benefits of using a nonuniform array (i.e. one including joints of different size and shape) are explored.