ITherm (http://www.ithermconference.org/) and ECTC (http://www.ectc.net/) are two important conferences in electronic packaging and systems. They are normally located at the same hotel and the same time. The attendees can register for both confercences by paying $100 extra. The total attendance of the two conferences is about 1500. The page counts of the proceedings of the two conferences together is more than 1600 every year. ITherm is more modeling and simulation focused. It is a very good opportunity for mechanicians to meet enigeers in semiconductor industry.

ITherm 2008

 
   This is a stress modeling position in TI's research
organization Silicon Technology Development (SiTD). The opening is
immediate and the position is filling very fast. Minimum requirement:
MS degree in the following fields: Mechanical Engineering, Physics,
Materials Science or Engineering Mechanics. PhD degree is preferred. 
Please email your resume to Jie-Hua (Jeff) Zhao at jhzhao@ti.com or
Darvin Edwards at rvin@ti.com. Call Jeff at 972-995-8851 for detail.
Job description is listed below:

Flip-chip plastic ball grid array (FC-PBGA) packages are widely used in high performance components. However, its die back is normally under tensile stress at low temperatures. This paper presents a probabilistic mechanics approach to predict the die failure rate in the FC-PBGA qualification process. The methodology consists of three parts:

1. die strength test using four-point bending (4PB) method;
2. the radius of curvature (ROC) measurement of the assembled FC-PBGA at room temperature;
3. Finite element method (FEM) stress analysis.

Jie-Hua Zhao, Peng Su, Min Ding, Sheila Chopin, and Paul S. Ho

A 3-dimensional finite element method (FEM) model considering the elasticity anisotropy, thermal expansion anisotropy and plasticity of β-Sn is established. The Voronoi diagrams are used to generate the geometric patterns of grains of the Sn coating on Cu leadframes. The crystal orientations are assigned to the Sn grains in the model using the x-ray diffraction (XRD) measurement data of the samples. The model is applied to the Sn-plated package leads under thermal cycling tests. The strain energy density (SED) is calculated for each grain. It is observed that the samples with higher calculated SED are more likely to have longer Sn whiskers and higher whisker density. The FEM model, combined with the XRD measurement of the Sn finish, can be used as an effective indicator of the Sn whisker propensity. This may expedite the qualification process significantly.