Title :
Threshold voltage shift in FIB circuit edit of embedded flash device
Author :
Yeoh, Joon Chai ; Chong, K.C. ; Khairizam, A.R. ; Sim, Mei-Mei I. ; Lee, Meng Chuan ; Li, Susan
Author_Institution :
Spansion (Penang) Sdn. Bhd., Bayan Lepas, Malaysia
Abstract :
This study presents FIB modification effect on pre-programmed Flash devices, sampled from 2 process technologies. No Vt shift is observed during FIB milling with or without the XeF2 etching gas for enhanced milling process. But FIB-induced metal deposition causes significant amount of Vt shift. The maximum Vt shift of 400 mV in FIB-induced tungsten deposition is considerably smaller when compared to the maximum of 800 mV in platinum deposition. To minimize the effect of Vt shift during FIB circuit-edit, tungsten deposition should be used for FIB editing of interconnects as part of the Flash design debug process. For Pt deposition of a specific area size and thickness, varying the FIB ion currents do not significantly change the amount of Vt shift.
Keywords :
coating techniques; flash memories; focused ion beam technology; integrated circuit design; sputter etching; FIB circuit edit; FIB milling; FIB-induced metal deposition; FIB-induced tungsten deposition; Flash device; XeF2 etching gas; embedded flash device; platinum deposition; threshold voltage shift; Debugging; Etching; Gases; Integrated circuit interconnections; Ion beams; Milling; Passivation; Surface charging; Threshold voltage; Tungsten;
Conference_Titel :
Physical and Failure Analysis of Integrated Circuits (IPFA), 2010 17th IEEE International Symposium on the
Conference_Location :
Singapore
Print_ISBN :
978-1-4244-5596-6
DOI :
10.1109/IPFA.2010.5532305