Comprehensive in situ (designed-in) diagnostic capabilities have been incorporated into digital microelectronic systems for years, yet similar capabilities are not commonly incorporated into the design of analog microelectronics. And as feature sizes shrink and back end interconnect metallization becomes more complex, the need for effective diagnostics for analog circuits becomes ever more critical. This paper presents concepts for incorporating in situ diagnostic capability into analog circuit designs. Aspects of analog diagnostic system architecture are discussed as well as nodal measurement scenarios for common signal types. As microelectronic feature sizes continue to shrink, diagnostic capabilities such as those presented here will become essential to the process of fault localization in analog circuits.

Many manufacturers in the microelectronics industry supply customers who increasingly demand ultra-low product failure rates. However, one of the least desirable scenarios for the microelectronic failure analyst is when analysis is required on a single failed unit. In these cases, the analyst loses the luxury of having “disposable” failing units in the analysis process. In the following discussion we present strategies to help the analyst more effectively find the failure mechanism for single unit failures.