Nondestructive Analysis of Signal Interconnection on Thermally Enhanced Ball Grid Array

As the package’s complexity and compactness grow, the challenge of nondestructive analysis becomes more difficult for the ultra-fine pitched interconnections and the heat spreader structures. To confront this analysis issue, the ultrafine-pitch wirebond interconnect with thermally enhanced heat spreader attached to the ball grid array (BGA) package are analyzed. Time-domain reflectometry (TDR) is being used increasingly to characterize the interconnection of thermal enhanced BGA (EBGA). We have proposed a TDR method for determining EBGA fault location base on between test waveform and open waveform by using open-end fixture (OEF). An OEF was employed to detect the rapid rise of edge signals from the package and to monitor them under the two parameters of time interval and reflection voltage. The TDR measurement results can determine both the failure location and type based on the above-mentioned parameters for an EBGA package. Then, a detailed failure analysis is performed by X-ray to confirm the experimental findings.