A Damage Evolution Model for Thermal Fatigue Analysis of Solder Joints

Abstract

Thermal fatigue of solder joints is critical to the performance and reliability of electronic components. It is well known that the fatigue life of solder joints is rather difficult to be estimated because of the complicated material behaviors and solder joint geometry. Conventional life prediction methods such as Coffin-Manson equation or its modifications usually over-estimate the thermal fatigue life. The main reason for this phenomenon is that the material properties are assumed constant during thermal cycling. In this paper, a damage evolution model is introduced for predicting the thermal fatigue life of solder joints. This method not only considers the degradation of material properties in the solder, but also saves substantial computational effort. In the present study, a damage function is determined by the hysteresis loops of creep shear stress-strain of solder joints in a double-beam specimen. The proposed model is then applied to investigate the solder joint reliability of a 272 PBGA package and a bottom-leaded plastic (BLP) package for model verification. The results from the present analysis seem to be encouraging. [S1043-7398(00)01003-3]

Constitutive and damage model for a lead-free solder

“…28 None of these variables, however, corresponds to a unique physical damage state of the material. Here D is defined as a function of the physical damage metric w. In this way, D and the damage state have a one-to-one relationship.…”

Board level solder joint reliability analysis of a fine pitch Cu post type wafer level package (WLP)

“…Steady-state creep is described by a single hyperbolic-sine function [9] as follows: where de s /dt is the steady-state strain rate, n is the stress exponent, Q is the activation energy, j is the Boltzmann constant (8.63 · 10 À5 eV/K), T is the absolute temperature, A is a material constant, r is the applied stress, and a is the stress level at which the Power law dependence breaks down. The creep properties of 63Sn-37Pb solder are taken from the existing literature [9][10][11][12][13][14][15][16][17]. In the subsequent solder joint reliability analysis, the material properties of other materials are listed in Table 1 [18-21,30-38].…”

“…Assembly on Printed Circuit board (PCB) involves standard surface mount technology (SMT) operations -printing solder paste on PCB, component placement, reflow and clean (depending on the flux type) [14][15][16][17][18][19][20][21][22][23]. The PCB used is 2 metal layers FR4 board.…”

Fatigue damage modeling in solder interconnects using a cohesive zone approach

“…This assumption results in underestimated values of the fatigue life because in reality, repeated cycling results in a gradual degradation of the solder material (Basaran et al, 2001). This has been emphasized experimentally through the observation that creep hysteresis loops of solder materials collapse over the thermal cycles (Zhang et al, 2000). Moreover, solder joint fatigue models were developed based on experimental thermal cycling tests on macroscopic specimens.…”