Query: Integrated On-Chip Inductors using magnetic material

Candidate papers:

abstract: On chip inductors with magnetic material are integrated into both advanced 130 and 90 nm complementary metal oxide semiconductor processes. The inductors use aluminum or copper metallization and amorphous CoZrTa magnetic material. Increases in inductance of up to 28 times corresponding to inductance densities of up to 1.3 m H mm 2 were obtained, significantly greater than prior values for on chip inductors. With such improvements, the effects of eddy currents, skin effect, and proximity effect become clearly visible at higher frequencies. The CoZrTa was chosen for its good combination of high permeability, good high temperature stability 250 deg C high saturation magnetization, low magnetostriction, high resistivity, minimal hysteretic loss, and compatibility with silicon technology. The CoZrTa alloy can operate at frequencies up to 9.8 GHz but trade offs exist between frequency, inductance, and quality factor. The effects of increasing the magnetic thickness on the permeability spectra were measured and modeled. The inductors use magnetic vias and elongated structures to take advantage of the uniaxial magnetic anisotropy. Techniques are presented to extract a sheet inductance and examine the effects of magnetic vias on the inductors. The inductors with thick copper and thicker magnetic films have resistances as low as 0.04 O and quality factors up to 8 at frequencies as low as 40 MHz.
author_names: Donald S Gardner

Gerhard Schrom

Peter Hazucha

Fabrice Paillet

Tanay Karnik

Shekhar Beaverton Borkar

Roy Hallstein

T Dambrauskas

Charles Hill

C D Linde

Wojciech Worwag

Robert Baresel

Sriram Muthukumar
title: Integrated on chip inductors using magnetic material (invited)
year: 2008

abstract: In this paper we present ultra low loss magnetic inductors integrate able in the far BEOL across technology nodes for power management applications such as DC DC convertors. Our inductors have inductance densities as high as 158 nH/mm2 up to 100 MHz, Q factors >20 and a high saturation current of 1.77 A in 1mm2 area with 50 um thickness. The inductors also maintain a Q factor >10 after considering the large signal losses, which makes them suitable for handling high DC load currents and large AC ripples at high frequencies, such as in integrated voltage regulators. This is possible by using a highly optimized laminated magnetic material as core that enables very high saturation current and ultra low losses. Hence, our inductors can replace the existing on board, bulky and lossy inductors in power convertors including voltage regulators for CPUs/GPUs.
author_names: Zishan Ali

Lulu Peng

Patrick Rohlfs

Yong Chau Ng

Lothar Lehmann

Chor Shu Cheng

Lawrence Selvaraj

Marcel Wieland
title: Ultra low loss on chip magnetic inductors in the far BEOL for high frequency power electronics
venue: 2021 33rd International Symposium on Power Semiconductor Devices and ICs (ISPSD)
year: 2021

abstract: Integrated on chip inductors with high quality factors are demonstrated using a low loss artificial conductor technology. This concept is based on an artificial layered meta material comprising a bi layered Ni80Fe20/Cu superlattice. By properly tailoring the thickness ratio between the non magnetic and magnetic metallic layers, the skin effects can be effectively suppressed within a wide frequency range, and can be tuned to a minimum at the frequency of interest up to 67 GHz. The quality factor has been increased by 41% of a 2nH inductor at 14.5GHz. The bandwidth of skin effect suppression is obtained between 10 18 GHz.
author_names: I Iramnaaz

T Sandoval

Y Zhuang

Hugo Schellevis

B Rejaei
title: High quality factor RF inductors using low loss conductor featured with skin effect suppression for standard CMOS/BiCMOS
venue: 2011 IEEE 61st Electronic Components and Technology Conference (ECTC)
year: 2011

abstract: FO WLP with integrated solenoidal magnetic core inductor in the RDL layer was proposed and developed in this work. This provide a packaging solution to integrate high performance inductors for high efficiency power conversion to the embedded device chips without sacrificing valuable chip estate as compared to integrating the inductors on the surface of device chip. Two photo dielectric materials were evaluated and it was found that material with higher tensile strength and percent elongation was able to sustain the magnetic film deposition and patterning process without showing cracks or delamination. Different patterning methods of the magnetic film were explored. Wet etching method has residue issues on low lying features in valley and contact vias. The sidewall of the magnetic core was highly sloped for thicker magnetic film due isotropic nature of the wet process. Dry etching was inefficient to etch the thick magnetic film. A new patterning method was developed to overcome the wet etching issues to produce magnetic core with vertical sidewall with no residue issues. Electrical characterization was performed on the fabricated inductor. The inductor shows a flat inductance response up to its self resonance frequency, and a quality factor of 14 can be achieved. These indicates that the inductor has low loss and can be utilized in high efficient power conversion.
author_names: Soh Siew Boon

David Ho Soon Wee

Raju Salahuddin

Ravinder Pal Singh
title: Magnetic Inductor Integration in FO WLP using RDL first Approach
venue: 2019 IEEE 21st Electronics Packaging Technology Conference (EPTC)
year: 2019

abstract: A novel on chip magnetic bead separator using micromachined magnetic tips for biocell sorting in microfluidic systems is presented. Magnetic interconnection technology is applied by using through holes filled with NiFe permalloy material, which allows the fully integrated electromagnetic inductors to be placed underneath the device chip. Only the magnetic tips on the front side of the chip are exposed to integrated microchannels, which give wide flexibility in constructing microfluidic systems with the magnetic bead separator. Magnetic beads were separated effectively from a continuous flow using the developed on chip magnetic bead separator.
author_names: Rong Rong

Jin-Woo Choi

Chong H Ahn
title: An on chip magnetic bead separator for biocell sorting
year: 2006

abstract: Inductors are important components of analog circuit designs, from matching circuitry to passive filters. In this study, the application of electrophoretically deposited nano ferrite material has been investigated as a technique to increase the inductance of integrated copper planar inductors fabricated using copper plating and chemical mechanical planarization. Sintered Mn Zn ferrite particles are suspended in a medium of isopropyl alcohol with magnesium nitrate and lanthanum nitrate salts. The transportation of the particles to the substrate surface is assisted by applied electric field and particles adhere to the substrate surface by a glycerol based surfactant. Electrophorectic deposition process forms a self aligned polymeric thin film on the surface of a p type silicon substrate selectively with respect to copper. This ferrite deposition method yields high selectivity to the inductor coils and patterned silicon substrates compatible with standard silicon technology.
author_names: Cody M Washburn

Daniel Brown

Jay Cabacungan

Jayanti Venkataraman

Santosh Kurinec
title: Application of Magnetic Ferrite Electrodeposition and Copper Chemical Mechanical Planarization for On Chip Analog Circuitry
year: 2005

abstract: Improved Resistivity (r) and Anisotropy field (Hk) could result in CoP performance greater than sputttered CoTaZr, with improved performance at high frequency and an increased deposition rate Acknowledgements: Intel Corporation Enterprise Ireland Tyndall National Institute References i D.S. Gardner, G. Schrom, P. Hazucha, et al. "Integrated on chip inductors using magnetic material" J. Appl. Phys. 103, 07E927 1 (2008) ii Satish Prabhakaran et al. IEEE Trans. On Magnetics. 39, 3190 (2003) iii D.S. Gardner, G. Schrom, P. Hazucha, et al. "Integrated on chip inductors using magnetic material" J. Appl. Phys. 103, 07E927 1 (2008) iv W.P. Jayasekara, J.A. Mabin, M.H. Kryder, IEEE T. Mag. 34(4) 1438 (1998) High frequency complex permeability curves for selected magnetic materials and fit to theoretical model 200 0 200 400 600 80
author_names: Brice Jamieson

Paul McCloskey

Saibal Roy
title: Optimization of magnetic enhancement layers for high frequency transmission line micro inductors
year: 2008

abstract: Recently, more and more applications have used planar inductors not only on silicon substrate but also on ceramic or polymer substrates (rigid or flex) Inductors integrated in today's silicon process could not fulfil the requirements for performance of modern communication equipments. Sometimes for system in package applications high quality inductors and other passive components are placed outside from chip and are realized using organic or non organic substrate. This paper presents the results of investigation on the planar inductor as electrical performance (inductance, quality factor, self resonance frequency) according with manufacturing technology and substrate (organic or non organic) shape (square or spiral) number of layers (single or double layer) The influence of a magnetic material and it's influence on overall parameters of the inductor will also be analyzed
author_names: Paul Svasta

Ciprian Ionescu

Virgil Golumbeanu

Norocel Codreanu

A Romanescu

Alena Pietrikova

Jenica Neamtu
title: Electromagnetic Behavior of Inductive Planar Structures with Non Homogenous Magnetic Environment
venue: 2006 1st Electronic Systemintegration Technology Conference
year: 2006

author_names: Donald S Gardner

Gerhard Schrom

Fabrice Paillet

Tanay Karnik

Shekhar Beaverton Borkar
title: Integrated On Chip Inductors Using Magnetic Materials
year: 2011

abstract: On chip strip line coupled inductors integrated with magnetic material are a promising technology option to enable on chip voltage regulators for improving power management in microelectronics. We report on design methodologies where several examples of parameter tradeoffs are presented. When considered with practical integration constraints, these result in an optimized structure. Strip line inductors integrated with Ni80Fe20 were then fabricated, electrically characterized, and compared to models. Electrical characterization included frequency dependent measurements of effective self and mutual inductance, effective resistance, coupling coefficient, and saturation effects.
author_names: P Morrow

Chang-min Park

H W Koertzen

J T DiBene
title: Design and Fabrication of On Chip Coupled Inductors Integrated With Magnetic Material for Voltage Regulators
venue: IEEE Transactions on Magnetics
year: 2011