Abstract
This paper reports on an inductor fabrication method capable to deliver high quality factor (Q) and high self-resonance frequency (SRF) devices using quartz insulating substrates and thick high-conductivity copper lines. Inductors are key devices in RF circuits that, when fabricated on traditional semiconductor substrates, suffer from poor RF performances due to thin metallization and substrate related losses. Many previous works revealed that RF performances are strongly dependent on the limited metallization thickness and on the conductivity of the substrate. In this paper we demonstrate a new fabrication process to improve the Q factor of spiral inductors by patterning thick high conductive metal layers directly in a dielectric substrate. Moreover, we develop and validate accurate equivalent circuit modeling and parameter extraction for the characterization of the fabricated devices.
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References
Bahl I (2003) Lumped elements for RF and microwave circuits. Artech House, Boston
Carchon GJ, de Raedt W, Beyne E (2004) Wafer-level packaging technology for high-Q on-chip inductors and transmission lines. IEEE Trans Microw Theory Tech 52:1244–1251
Kim BK, Ko BK, Lee KK (1995) Monolithic planar RF inductor and waveguide structures on silicon with performance comparable to those in GaAs MMIC. IEDM Tech Digest pp 717–720
Lakdawala H, Zhu X, Luo H, Santahannan S, Carley LR, Fedder GK (2002) Micromachined high-Q inductors in a 0.18-μm copper interconnect low-k dielectric CMOS process. IEEE J Solid State Circuits 37:394–403
Mohan SS, M.M. Hershenson MM, S.P. Boyd SP, T.H. Lee TH (1999) Simple accurate expression for planar spiral inductances. IEEE J Solid State Circuits 34:1419–1424
Ozgur M, Zaghloul M, Gaitan M (1999) High Q backside Micromachined CMOS inductors. IEEE Int Symp Circuits Syst 2:577–580
Pavius M, Hibert C, Flückiger P, Renaud P (2004) Profile angle control in SiO2 deep anisotropic dry etching for MEMS fabrication. In: Proceedings of MEMS 2004, pp 669–672
Pisani MB, Hibert C, Bouvet D, Beaud P, Ionescu AM (2004) Copper/polyimide fabrication process for above-IC integration of high quality factor inductors. Microelectron Eng 73–74:474–479
Reyes AC, El-Ghazaly SM, Dorn S, Dydyk M, Schroder DK, Patterson H (1996) High-resistivity silicon as a microwave substrate. In: Proceedings of electronic components and technology conference, pp 382–391
Yoon JB, Kim BK, Han CH, Yoon E, Kim CK (1999) Surface micromachining solenoid on-Si and on-glass inductors for RF applications. IEEE Electron Devices Lett 20(9):487–489
Yue CP, Wong SS (2000) Physical modeling of spiral inductors on silicon. IEEE Trans Electron Devices 47:560–568
Acknowledgments
The authors thank the IST Wide-RF project (IST-2001-33286), the Swiss OFES project 01.0308 and the IST MIMOSA project (IST-2002-507045) for funding. We thank Mr. Giancarlo Corradini from the EPFL-LPM (Laboratoire de Production Microtechnique) for providing the gold wire-bonding services. Many thanks are due to the EPFL-CMI staff for the clean room facilities access and supplied technical support.
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Leroy, C., Pisani, M.B., Hibert, C. et al. High quality factor copper inductors integrated in deep dry-etched quartz substrates. Microsyst Technol 13, 1483–1487 (2007). https://doi.org/10.1007/s00542-006-0364-z
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DOI: https://doi.org/10.1007/s00542-006-0364-z