Cold electronics is a key technology in many areas of science and technology including space exploration programs and particle physics. A major experiment with a very large number of analog and digital electronics signal processing channels to be operated at cryogenic temperatures is the next-generation neutrino experiment, the Deep Underground Neutrino Experiment (DUNE). The DUNE detector uses liquid Argon at 87K as a target material for neutrinos, and as a medium to track charged particles resulting from interactions in the detector volume. The DUNE electronics [1] consists of custom-designed ASIC (Application Specific Integrated Circuits) chips based on low power 180 nm-CMOS technology. The main risk for this technology is that the electronics components will be immersed in liquid argon for many years (20-30 years) without access. Reliability issues of ASICs may arise from thermal stress, packaging, and manufacturing-related defects: if undetected those could lead to long-term reliability and performance problems. The scope of this paper is to explore non-destructive evaluation techniques for their potential use in a comprehensive quality control process during prototyping, testing and commissioning of the DUNE cold electronics system. Specifically, we have used the Scanning Acoustic Microscopy and X-ray tomography to study permanent structural changes in the ASIC chips associated with thermal cycling between the room and cryogenic temperatures.
Download