Failure Analysis for System in Package devices using Magnetic Microscopy

As new technologies in the electronic environment develop from 2D Integrated Circuits to 3D complex packages, it becomes necessary to find new techniques to detect and localize the different kinds of failures. The project carried out by the author, led by Dr. Philippe Perdu, is aimed to find a solution to localize defects for System in Package (SiP) devices. This is done by measuring the magnetic field, which is generated by the current owing through the device, with a Magnetic Microscope (Magma C20) and comparing it with several simulated faults in order to choose the most probable one.

In Chapter 2 there is a short description of the work environment, specifying the general purpose of CNES and the Expertise Laboratory work which is where this project evolved.

In Chapter 3 the Failure Analysis problem is discussed and a short description of the existing techniques is given.

To fully understand the new developed technique, in Chapter 4 and Chapter 5, firstly, how static currents generate a magnetic field is described (Biot-Savart Law). Following this, how to nd the current distribution analytically once given the map of the magnetic eld is shown.

In Chapter 6 the author's work on the evaluation of three different simulation software is described together with some background theory on Finite Element Analysis.

For the hardware tool used to map the magnetic eld, a SQUID device was chosen after comparing several magnetic sensors, as described in Chapter 7.

Chapter 8 describes how a sample was designed and manufactured, and how different simulations of it were done.

In Chapter 9 the tool used to take the measurements and the measurements taken are described.

Finally in Chapter 10 the correlation between the simulation and the measurements was calculated to validate the new technique.