Fracture mechanics analysis of the effect of substrate flexibility on solder joint reliability

Solder joint fatigue failure is a serious reliability concern in area array technologies, such as flip chip and ball grid array packages of integrated-circuit chips. The selection of different substrate materials could affect solder joint thermal fatigue life significantly. The reliability of solder joints in real flip chip assembly with both rigid and compliant substrates was evaluated by the accelerated temperature cycling test and thermal mechanical analysis. The mechanism of substrate flexibility on improving solder joint thermal fatigue lifetime was investigated by fracture mechanics methods. Two different methods (crack tip opening displacement, CTOD and virtual crack closure technique, VCCT) are used to determine the crack tip parameters which are considered as the indices of reliability of solder joints, including the strain energy release rate and phase angle for the different crack lengths and temperatures. It was found that the thermal fatigue lifetime of solder joints in flip chip on flex assembly (FCOF) was much longer than that of flip chip on rigid board assembly (FCOB). The flex substrates could dissipate energy that otherwise would be absorbed by solder joints, that is, substrate flexibility has a great effect on solder joint reliability and the reliability improvement was attributed to flex buckling or bending during thermal cycling.

[1]  Francesco Caputo,et al.  Evaluation of energy release rate for delamination defects at the skin/stringer interface of a stiffened composite panel , 2004 .

[2]  J. Rice.  A path-independent integral and the approximate analysis of strain , 1968 .

[3]  Z. Suo,et al.  Mixed mode cracking in layered materials , 1991 .

[4]  I. Raju.  Calculation of strain-energy release rates with higher order and singular finite elements , 1987 .

[5]  S. A. Fawaz,et al.  Stress intensity factor solutions for part-elliptical through cracks , 1999 .

[6]  Jean-Michel Vinassa,et al.  Strategy for designing accelerated aging tests to evaluate IGBT power modules lifetime in real operation mode , 2003 .

[7]  S. H. Ho,et al.  Board level reliability of PBGA using flex substrate , 2001, Microelectron. Reliab..

[8]  J. Lau.  Ball Grid Array Technology , 1994 .

[9]  Sudipta K. Ray,et al.  Device interconnection technology for advanced thermal conduction modules , 1992 .

[10]  J. H. Lau,et al.  Fracture Mechanics Analysis of Low Cost Solder Bumped Flip Chip Assemblies With Imperfect Underfills , 2000 .

[11]  Andrew A. O. Tay,et al.  The impact of moisture diffusion during solder reflow on package reliability , 1999, 1999 Proceedings. 49th Electronic Components and Technology Conference (Cat. No.99CH36299).

[12]  David A. Dillard,et al.  Effect of substrate flexibility on solder joint reliability , 2002, Microelectron. Reliab..

[13]  C. Gillot,et al.  Double-sided cooling for high power IGBT modules using flip chip technology , 2001 .

[14]  F. Barlow,et al.  Low cost flex substrates for miniaturized electronic assemblies , 2002, Microelectron. Reliab..

[15]  J. H. Lau,et al.  Effects of underfill material properties on the reliability of solder bumped flip chip on board with imperfect underfill encapsulants , 2000 .

[16]  L. Anand,et al.  An internal variable constitutive model for hot working of metals , 1989 .

[17]  James Keating.  Transition of MCM-C applications to MCM-L using rigid flex substrates , 1998 .

[18]  M. M. Abdel Wahab,et al.  On the use of fracture mechanics in designing a single lap adhesive joint , 2000 .

[19]  X. Chen,et al.  Effect of substrate flexibility on solder joint reliability. Part II: finite element modeling , 2005, Microelectron. Reliab..

[20]  Guo-Quan Lu,et al.  Chip-scale packaging of power devices and its application in integrated power electronics modules , 2000, ECTC 2000.

[21]  James R. Rice,et al.  Elastic Fracture Mechanics Concepts for Interfacial Cracks , 1988 .

[22]  L. Anand.  Constitutive equations for hot-working of metals , 1985 .

[23]  Hans Albert Richard,et al.  Fracture analyses and experimental results of crack growth under general mixed mode loading conditions , 2004 .

[24]  M. Kanninen,et al.  A finite element calculation of stress intensity factors by a modified crack closure integral , 1977 .

[25]  A. Giannakopoulos,et al.  Modeling of facesheet crack growth in titanium–graphite hybrid laminates, Part I , 2003 .