High-frequency micro-machined power inductors

Wang, N.; O’Donnell, Terence; Roy, Saibal; Brunet, Magali; McCloskey, Paul; O’Mathuna, S.C.

doi:10.1016/j.jmmm.2004.11.434

Cited by 35 publications

(13 citation statements)

References 7 publications

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“…Permalloy (Ni 80 Fe 20 ) was chosen as the magnetic core material. Owing to its high permeability, high saturation flux density [11], and suitability for microfabrication, the material could be formed through electroplating. The current density of 5 mA/cm 2 was optimized for electroplating, as the maximum current does not yield bubbles inside the material during electroplating, thus achieving a smooth surfac e. At this current density, the deposition rate of metal was 8 μm/h.…”

Section: Magnetic Corementioning

confidence: 99%

Metal-Embedded SU-8 Slab Techniques for Low-Resistance Micromachined Inductors

Mapato

Klysuban²,

Kulworawanichpong

et al. 2018

IJRES

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This work presents new fabrication technique for micro power-inductors by using metal-embedded SU-8 slab techniques. This techniques used X-ray lithography to fabricate high aspect-ratio LIGA-like micro-structures in form of embedded structure in SU-8 slab and applied for inductor’s winding fabrication with aspect-ratio of 10. Thishigh-aspect ratiostructure can provide very low resistance winding but preserve small form factor and low profile. Inductors were designed as pot-core structures with8 μm-thick permalloy core and 250 μm-thick copper winding. 4-types of inductors were fabricated including 3, 5, 10 and 16 turns in the area of 1.8 mm2 to 9.5 mm2. All inductors have overall heights of 370 μm, measured inductance value in a range of 70 nH to 1.3 μH at 1 MHz and DC resistance value of 30 mΩ to 336 mΩ for 3 turns to 16 turns respectively. From this result, high aspect-ratio inductors show<span style="font-size: 10.0pt; font-family: 'Times New Roman','serif'; mso-fareast-font-family: Calibri; mso-bidi-font-family: 'Cordia New'; mso-bidi-theme-font: minor-bidi; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: TH;"> good results including low-resistance, high inductance, and a small form factor as expected.

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Section: Magnetic Corementioning

confidence: 99%

Metal-Embedded SU-8 Slab Techniques for Low-Resistance Micromachined Inductors

Mapato

Klysuban²,

Kulworawanichpong

et al. 2018

IJRES

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“…Performance of the microinductor with the anisotropic nanolaminated CoNiFe core is also compared with other microinductors with electrodeposited magnetic cores [4,9,[15][16][17][18][19][20][21][22][23]. These microinductors feature solenoid, spiral, or race track geometries and the magnetic cores comprise typically alloys of nickel, iron, and cobalt.…”

Section: Solenoid Microinductor With Nanolaminated Conife Corementioning

confidence: 99%

Anisotropic nanolaminated CoNiFe cores integrated into microinductors for high-frequency dc–dc power conversion

Kim

et al. 2015

J. Phys. D: Appl. Phys.

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This paper presents a rectangular, anisotropic nanolaminated CoNiFe core that possesses a magnetically hard axis in the long geometric axis direction. Previously, we have developed nanolaminated cores comprising tens to hundreds of layers of 300-1000 nm thick metallic alloys (i.e. Ni 80 Fe 20 or Co 44 Ni 37 Fe 19) based on sequential electrodeposition, demonstrating suppressed eddy-current losses at MHz frequencies. In this work, magnetic anisotropy was induced to the nanolaminated CoNiFe cores by applying an external magnetic field (50-100 mT) during CoNiFe film electrodeposition. The fabricated cores comprised tens to hundreds of layers of 500-1000 nm thick CoNiFe laminations that have the hard-axis magnetic property. Packaged in a 22-turn solenoid test inductor, the anisotropic core showed 10% increased effective permeability and 25% reduced core power losses at MHz operation frequency, compared to an isotropic core of the identical geometry. Operating the anisotropic nanolaminated CoNiFe core in a step-down dc-dc converter (15 V input to 5 V output) demonstrated 81% converter efficiency at a switching frequency of 1.1 MHz and output power of 6.5 W. A solenoid microinductor with microfabricated windings integrated with the anisotropic nanolaminated CoNiFe core was fabricated, demonstrating a constant inductance of 600 nH up to 10 MHz and peak quality factor exceeding 20 at 4 MHz. The performance of the microinductor with the anisotropic nanolaminated CoNiFe core is compared with other previously reported microinductors.

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“…The magnetics on silicon technology is based on a combination of electroplated, thin film, magnetic materials (NiFe permalloy core), used extensively in the magnetic disk head industry, with wafer-level, back-end-of-line (BEOL), electroplated copper conductors (windings) from the power semiconductor industry. Figures 5 and 6 show plan views and cross-sections of typical micro-inductor and micro-transformer devices based on a single-layer metal (SLM) and double-layer metal (DLM) process [50,51]. Figure 7 shows the process flows for both the SLM and DLM devices.…”

Section: Magnetics On Silicon Technologymentioning

confidence: 99%