Testing station for fast screening of through silicon via-enabled application-specific integrated circuits for hard x-ray imaging detectors

Abstract

Application-specific integrated circuits (ASICs) are used in space-borne instruments for signal processing and detector readout. The electrical interface of these ASICs to frontend printed circuit boards is commonly accomplished with wire bonds. Through silicon via (TSV) technology has been proposed as an alternative interconnect technique that will reduce assembly complexity of ASIC packaging by replacing wire bonding with flip-chip bonding. TSV technology is advantageous in large detector arrays where TSVs enable close detector tiling on all sides. Wafer-level probe card testing of TSV ASICs is frustrated by solder balls introduced onto the ASIC surface for flip-chip bonding that hamper alignment. Therefore, we developed the ASIC test stand (ATS) to enable rapid screening and characterization of individual ASIC die. We successfully demonstrated ATS operation on ASICs originally developed for CdZnTe detectors on the Nuclear Spectroscopic and Telescope Array (NuSTAR) mission that were later modified with TSVs in a via-last process. We tested both backside blind-TSVs and frontside through-TSVs, with results from internal test pulser measurements that demonstrate performance equal to or exceeding the probe card wafer-level testing data. The ATS can easily be expanded or duplicated to parallelize ASIC screening for large area imaging detectors of future space programs.

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