Evaluation of Fatigue Crack Propagation Behavior of Pressurized Sintered Ag Nanoparticles and Its Application to Thermal Fatigue Life Prediction of Sintered Joint

Abstract

Fatigue crack propagation rate of pressure-sintered Ag nanoparticles was investigated and prediction method of fatigue crack propagation using strain energy density computed by FEM was proposed. The fatigue crack propagation rate was lower than that of pressureless-sintered Ag nanoparticles around ambient temperature. At high temperature, multiple small cracks occurred ahead of a main crack and they were connected with one another and the propagation rate of the main crack increased, so that properties of fatigue crack propagation in the high temperature region were close to those of pressureless-sintered Ag nanoparticles.As the inelastic strain energy density and the length of its acquisition area were inversely proportional, the prediction of fatigue crack propagation that do not depend on the size of the area was possible by the use of the proportional constant of the relationship. The behavior of thermal fatigue crack propagation of sintered joint structure that was predicted by the derived fatigue crack propagation law was mostly in agreement with experimental behavior. [

Evaluation of Fatigue Crack Propagation of Sn–5.0Sb/Cu Joint Using Inelastic Strain Energy Density

“…becomes inversely proportional. As for this inversely proportional relationship, similar results had been obtained in sintered Ag nanoparticles 7,13) and the inverse relationship can be established regardless of materials. Furthermore, W in calculated as an average in the square area has negligible effects of element size in the square area.…”

Recent Development of Joining and Conductive Materials for Electronic Components

“…The joining reliability of sintered materials has been evaluated using high-temperature aging test, 6972) thermal cycle test, 7375) fatigue test and FEM analysis. 25,76) In predicting thermal fatigue life, as shown in Fig. 3, the fatigue crack propagation law of Paris type holds between fatigue crack propagation rate of pressure-sintered Ag nanoparticles and the inelastic strain energy density range (¦W in ) near the fatigue crack tip region.…”

“…6). 17) The issue introduces research related to electronic materials: evaluations of mechanical properties of solder alloys 1821) and metal materials used in electronic equipment parts, 22) investigation of intermetallic compounds formed on bonding wires, 23) development of resin materials, 24) and evaluations of fatigue properties of sintered materials, 25) solder alloys 26) and underfill resin. 27) From these special issues, there are 18 researches on joining materials and 4 researches on conductive materials, which shows the importance of these materials.…”

Novel Fatigue Crack Propagation Analysis of Solder Joint Using Singularity of Strain Energy Density in the Crack Tip Near Field

“…Fig. 1 Illustration of HRR singularity field and acquisition area of W. 11,12) Fig. 2 Relationship between W in and L area for Sn5.0Sb solder.…”

“…Other researchers have proposed an evaluation method using ¦W in-c as a parameter calculated from the HRR (Hutchinson-Rice-Rosengren) singularity 810) of the inelastic strain energy density ¦W in around the crack tip and have evaluated the fatigue crack propagation of die-attach materials, 11,12) an outline of which is described below. At loading levels that exceed small-scale yielding, the HRR singularity field is formed around the crack tip; the stress and strain singularities in the area are described by eq.…”