DocumentCode :
1949857
Title :
Influence of filler settling on the analysis of solder reliability of flip chip packaging
Author :
Chen, Cheng-fu ; Karulkar, Pramod C.
Author_Institution :
Dept. of Mech. Eng., Univ. of Alaska Fairbanks, Fairbanks, AK
fYear :
2008
fDate :
27-30 May 2008
Firstpage :
1719
Lastpage :
1723
Abstract :
In the capillary-flow underfilling process many practical evidences suggest that the distribution of fillers is not uniform as is usually assumed. It is likely caused by filler sedimentation, variation of the flow pattern, and rheology of uncured underfill flow, etc. Such a nonuniform distribution of fillers requires that we modify the reliability estimates of flip chip packages that are based on an ideal, isotropic underfill. This paper reports an analytical study of the influence of filler settling on the flip chip solder reliability analysis. By taking 35% for the volume fraction of silica fillers, we have described the y-dependent filler settling by three settling scenarios and calculated the thermomechanical properties of the underfill by considering three types of temperature-dependent, linearly elastic epoxy resins for each settling profile. In total, nine underfill materials were individually introduced in a 2D finite element flip chip package model to comparatively study the thermal response of flip chip solder joints that are surrounded by the underfill. The FE results showed that the inelastic shear strains steadily accumulate in the flip chip solder joints. The inelastic shear strains increase significantly as filler settling is introduced. We also observed that as the extent of filler settling increases, the average inelastic shear strain energy density associated with the outermost solder joint increases.
Keywords :
filler metals; filling; flip-chip devices; integrated circuit packaging; integrated circuit reliability; polymers; solders; capillary-flow underfilling process; filler settling; flip chip packaging; inelastic shear strain energy density; linearly elastic epoxy resins; reliability; solder joint; thermal response; thermomechanical properties; Capacitive sensors; Epoxy resins; Finite element methods; Flip chip; Flip chip solder joints; Joining materials; Packaging; Rheology; Silicon compounds; Thermomechanical processes;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Electronic Components and Technology Conference, 2008. ECTC 2008. 58th
Conference_Location :
Lake Buena Vista, FL
ISSN :
0569-5503
Print_ISBN :
978-1-4244-2230-2
Electronic_ISBN :
0569-5503
Type :
conf
DOI :
10.1109/ECTC.2008.4550212
Filename :
4550212
Link To Document :
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