by Jack Goho
Gideon Analytical Laboratories received four working and four defective integrated circuit packages for failure analysis. They were Xilink TQG144 packages. Integrated circuit packaging is the final stage of semiconductor device fabrication, in which the tiny block of semiconducting material is encased in a supporting case that prevents physical damage or corrosion. These integrated circuit packages come in a variety of styles including surface mount, chip carriers, and pin grid arrays. Once the packages are fabricated, they are mounted and connected to a printed circuit board (PCB). The failing Xilink TQG144 packages had an intermittent operation at elevated temperature. The goal was to determine why this was the case.
Failure analysis was undertaken. The input/output (I/O) on this device had a diode on all the inputs. This made the curve tracer ineffective at finding electrical discrepancies at these pins. Curve tracing between the integrated circuit power supply pin (Vcc) and the ground proved useful because in the failed devices, the two legs of the curve trace intersected prematurely. The two bad devices with the above curve traces and one good part were decapsulated to reveal the interconnects and die. The wires were removed and passivation tests were conducted. The Vcc power rail had a defect in the passivation in two failed devices. Debris was found protruding from the surface of one of the Vcc power rails. Thermal testing revealed the ground to Vcc was unstable, which indicated a problem with the die or wire bonds. This Xilink TQG144 package failed because of electrical overstress (EOS) or electrostatic discharge (ESD) at elevated temperatures.
Gideon Analytical Laboratories is the leading problem solver for the electronics industry. Over the past two decades, Gideon Analytical Laboratories has undertaken hundreds and hundreds of challenging failure analysis challenges. With expertise and experience in combination with state of the art scientific electronic analytical equipment, Gideon Analytical Laboratories has been able to solve hundreds of problems and assist numerous companies. Our goal is to help companies in the electronics industry save time and money by helping them manage the quality and reliability of their products.