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High-density interconnects, enabled by advanced CMOS Cu BEOL technologies, lead to closely placed metals layers. High-aspect ratio metal lines require extensive plasma etching processes, which may cause reliability concerns on inter metal dielectric (IMD) layers. This study presents newly proposed test patterns for evaluating the effect of plasma-induced charging effect on the integrity of IMD between closely placed metal lines. Strong correlations between the plasma charging intensities and damages found in IMD layers are found and analyzed comprehensively.

Correction: In the original publication [1] Fig. 3 was presented incorrect. The correct additional file has been included with this erratum and the original article has been updated to rectify this error.

A novel device for monitoring plasma-induced damage in the back-end-of-line (BEOL) process with charge splitting capability is first-time proposed and demonstrated. This novel charge splitting in situ recorder (CSIR) can independently trace the amount and polarity of plasma charging effects during the manufacturing process of advanced fin field-effect transistor (FinFET) circuits. Not only does it reveal the real-time and in situ plasma charging levels on the antennas, but it also separates positive and negative charging effect and provides two independent readings. As CMOS technologies push for finer metal lines in the future, the new charge separation scheme provides a powerful tool for BEOL process optimization and further device reliability improvements.