Carbonyl-Iron/Epoxy Composite Magnetic Core for Planar Power Inductor Used in Package-Level Power Grid

Abstract

Our research objective is to realize the basic technology for a next generation Package-Level Power Grid (PLPG) for plural application LSIs. In this study, a carbonyl-iron powder (CIP)/epoxy composite magnetic core, for large-current power inductor used for the main dc-dc converter in the PLPG, has been fabricated and evaluated. 54 vol.%-CIP/epoxy composite core made by screenprinting had a relative permeability of 7.5 and loss tangent of about 0.03 at 100 MHz. The planar power inductor using composite core was fabricated and evaluated, which had a quasi closed magnetic circuit consisting of low permeability composite core and embedded 35 m thick, 2-turn copper spiral coil. The fabricated inductor with a 1mm-square in size had 5.5 nH inductance, Q-factor of 15 at 100 MHz and 18 m dc coil resistance. Inductance was constant even when the superimposed dc current increased up to around 5.5 A. Index Terms-Package-level power grid, planar power inductor, carbonyl-iron/epoxy composite magnetic core

Embedded Planar Power Inductor in an Organic Interposer for Package-Level DC Power Grid

“…As already reported [4], we forecast that the next generation power delivery to LSIs will become a package-level dc power grid (PLPG). The PLPG will consist of a main buck dc-dc converter with large current inductor and several POL buck dc-dc converters for each application LSI.…”

“…BASF Co. showed that the non-reduction CIP has an onion skin structure [9], which may be due to the spherical iron layers form on a nucleus in the Fe-particle growth, and CIP has a narrow particle-size distribution with a mean diameter of 1.1 m. Fig.2 shows the static magnetization curve of the CIP [4]. The CIP had a saturation magnetization of about 2 T and small coercive force.…”

“…To realize the embedded power magnetics, we have developed a Zn-Fe ferrite planar spiral inductor [5], [6] embedded in an organic interposer. In addition, we have developed a carbonyl-iron/epoxy composite core planar spiral inductor as an on-package power magnetics [4]. We consider that the metal composite magnetic core made by low-cost printing method is suitable for the large current inductor, because its low permeability contributes toward larger margin in the superimposed dc current characteristic.…”

CMOS Switch Buck DC-DC Converter Fabricated in Organic Interposer with Embedded Zn-Fe Ferrite Core Inductor

“…Recently, the package-level DC power grid has been proposed 1) as the next generation power delivery to LSIs, which consists of a main buck DC-DC converter and the multiple POL converters integrated into the package. Since the power supply voltage for CMOS logic LSI has been lowered to 1 V or below, it is considered that the POL converter operates under low-voltage output condition.…”

Loss Reduction of Transformer for LLC Resonant Converter Using a Magnetoplated Wire

“…Reduction of the iron loss can be achieved using core materials with improved properties and by changing the core shape (10)- (14) . Copper loss is reduced by changing the wire's shape and winding form.…”