The Impact of the Connection Failure of Ground Solder Balls on Digital Signal Waveform

Abstract

Ball-grid array (BGA) packages are widely used in digital signal devices, whose reliability and signal integrity are critical. In this research, the impact of failed ground solder balls on digital signal waveforms was theoretically modeled and analyzed, and the results were experimentally verified. A 3-D electromagnetic field model of a digital signal transmission channel with failed ground solder balls was developed to analyze the signal transmission in the frequency domain. In addition, a time-domain waveform simulation system was developed to examine the changes in the digital signal waveforms before and after degradation. Based on the structural and signal transmission characteristics of the solder area with failed ground solder balls, an equivalent circuit model of the degraded solder area was developed, which accurately predicts the effect of the failed ground solder balls on the amplitude and rising edge of the digital signals. The results obtained from the simulation were validated using experimental tests. This study fully examines the effects of the location and number of failed ground solder ball on signal transmission in both the frequency and the time domain. It provides insight and guidance regarding the impact on signal integrity of such faults, which serves to assist in improved packaging reliability and the development of fault detection strategies for such electronic systems.