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Isolation enhancement in integrated circuits using dummy metal fill

TitleIsolation enhancement in integrated circuits using dummy metal fill
Publication TypeConference Paper
Year of Publication2008
AuthorsGaskill, S. G., V. S. Shilimkar, and A. Weisshaar
Conference Name2008 IEEE Radio Frequency Integrated Circuits Symposium (RFIC)
Pagination483 - 486
Date Published06/2008
Conference LocationAtlanta, GA
ISBN Number978-1-4244-1808-4
KeywordsCMP, grounding, isolation, metal fill, shielding

Metal fill patterning in modern IC processes is often viewed as parasitics to be minimized. Here, we use metal fills to improve isolation. The improved isolation comes at the cost of increased capacitive loading. This isolation-loading tradeoff is analyzed for various grounding strategies. It is found to be best to ground first inner metal-fill. The effect of finite ground impedance is analyzed. An assumed worst-case ground impedance path of 50Omega is shown to give sufficient grounding up to 10 GHz.