<span style="font-size: 9pt; font-family: 'Times New Roman', serif;">This work presents new fabrication technique for micro power-</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">inductors </span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">by using metal-embedded SU-8 slab techniques. This techniques used X-ray lithography to fabricate high aspect</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">-r</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">atio LIGA-like micro-structures in form of embedded structure in SU-8 slab </span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">and applied for inductor’s</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;"> winding </span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">fabrication </span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">with aspect-ratio of 10. This</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">high-aspect ratio</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">structure</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;"> can provide very low resistance winding but preserve small form factor and low profile. Inductors </span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">were</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;"> designed as pot-core structures with</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">8 μm-thick permalloy core and 250 μm-thick coppe</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">r</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;"> winding. 4-type</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">s</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;"> 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 </span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;">DC</span><span style="font-size: 9pt; font-family: 'Times New Roman', serif;"> resistance value of 30 mΩ to 336 mΩ for 3 turns to 16 turns respectively. From this result, high aspect-ratio inductors show</span><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. </span>

This work presents a new fabrication technique for micro power inductors by using metal-embedded SU-8 slab molding techniques. The proposed technique uses X-ray lithography to fabricate high-aspect-ratio LIGA-like microstructures in form of embedded structures in the SU-8 slab. This process was applied to fabricate an inductor’s windings with an aspect ratio of 10, which can provide very low resistance but still preserve a small form factor and low profile. Inductors were designed as pot-core structures with overall heights of 370 μm and embedded with 250-μm-thick windings. From the advantage of metal embedded SU-8 slab techniques, 8 μm-thick permalloy core could be fabricated by electroplating around the winding in a single step that could help simplify the process. Four types of inductors were fabricated with 3, 5, 10, and 16 turns in the area of 1.8 to 9.5 mm2. The measured inductance was in the range of 70 nH to 1.3 μH at 1 MHz and DC resistance of 30–336 mΩ for 3–16 turns, respectively. The DC resistance of fabricated inductor was low, as expected, and showed good result compared with the results in literature.