Title :
Effect of voids on the reliability of BGA/CSP solder joints
Author :
Yunus, M. ; Primavera, A. ; Srihari, K. ; Pitarresi, J.M.
Author_Institution :
Dept. of Syst. Sci. & Ind. Eng., State Univ. of New York, Binghamton, NY, USA
Abstract :
Voids in solder joints have been considered as a defect in electronics assembly. The factors that affect void formation are complex and involve the interaction of many other factors. There are no established standards for void size and void area in a solder joint for it to be deemed defective. Inspection criteria have been very subjective. The effect of voids on the reliability of a BGA/CSP solder joint may depend not only on the size, but also on other factors such as frequency and location. This study focused on investigating the effect of voids on the reliability of solder joints. The effect of void size, location and frequency on reliability were studied. Testing was done by a mechanical deflection testing (torsion) system and air to air thermal cycling (-40°/125°C). Failures were analyzed and failure modes were identified by cross sectional analysis. Additionally, a finite element model was developed for a package with voids of varying sizes in the corner solder joint of the package. The results from the model were compared with the results from reliability testing and are presented in this paper. Analysis indicates that voids reduce the solder joint life. Voids which are greater than 50% of the solder joint area decrease the mechanical robustness of the solder joints. Small voids also have an effect on reliability. However, this effect is dependent on the frequency and location of voids
Keywords :
ball grid arrays; chip scale packaging; failure analysis; finite element analysis; inspection; integrated circuit interconnections; integrated circuit modelling; integrated circuit reliability; integrated circuit testing; mechanical testing; thermal stresses; torsion; voids (solid); -40 to 125 C; BGA solder joints; CSP solder joints; air to air thermal cycling; corner solder joint; cross sectional analysis; defective solder joint; electronics assembly; failure analysis; failure modes; finite element model; inspection criteria; mechanical deflection testing system; mechanical robustness; package voids; reliability; reliability testing; solder joint life; solder joints; torsion system; void area; void effects; void formation; void frequency; void location; void size; Assembly; Failure analysis; Frequency; Industrial engineering; Instruments; Mechanical engineering; Packaging; Robustness; Soldering; System testing;
Conference_Titel :
Electronics Manufacturing Technology Symposium, 2000. Twenty-Sixth IEEE/CPMT International
Conference_Location :
Santa Clara, CA
Print_ISBN :
0-7803-6482-1
DOI :
10.1109/IEMT.2000.910730
