Cryogenic acoustic microscopy and evaulation of electronic components

Abstract

Electronics operating at cryogenic temperatures are essential in fields like space exploration and particle physics. The Deep Underground Neutrino Experiment (DUNE), a next generation particle physics experiment, will rely on tens of thousands of custom designed application specific integrated circuits (ASICs) operating directly in liquid argon (87 K) for decades without repair or replacement. Ensuring circuit functional reliability throughout the duration of the experiment is mission critical. Both functional and nondestructive testing are employed to safeguard circuit quality and reliability. Part of this work involves the design, testing, and data analysis of a cryogenic acoustic microscope (CryoSAM) operating at 15 MHz. The CryoSAM is capable of interrogating ASICs at both room temperature (300 K) and in liquid nitrogen (77 K), identifying acoustic anomalies likely arising from thermal stress and manufacturing-related defects, using a powerful correlation analysis technique. These anomalies can lead to functional degradation and suboptimal electronic performance of the circuit sensors. Image analysis and correlations are used to compare differences seen before and after cryogenic temperature cycling. Data are reported that were collected at both room temperature and when cooled using liquid nitrogen. Designs and challenges of operating the instrument at cryogenic temperatures are also discussed.