WO1998034287A1 - Elements inductifs integres sans trous d'interconnexions pour des applications electromagnetiques - Google Patents

Elements inductifs integres sans trous d'interconnexions pour des applications electromagnetiques Download PDF

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Publication number
WO1998034287A1
WO1998034287A1 PCT/US1998/001879 US9801879W WO9834287A1 WO 1998034287 A1 WO1998034287 A1 WO 1998034287A1 US 9801879 W US9801879 W US 9801879W WO 9834287 A1 WO9834287 A1 WO 9834287A1
Authority
WO
WIPO (PCT)
Prior art keywords
conductor elements
layer
magnetic core
spaced conductor
isolation
Prior art date
Application number
PCT/US1998/001879
Other languages
English (en)
Other versions
WO1998034287A9 (fr
Inventor
A. Bruno Frazier
Original Assignee
University Of Utah Research Foundation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University Of Utah Research Foundation filed Critical University Of Utah Research Foundation
Priority to JP53314298A priority Critical patent/JP2002513511A/ja
Priority to CA002279297A priority patent/CA2279297A1/fr
Priority to EP98903872A priority patent/EP1000442A4/fr
Priority to AU60524/98A priority patent/AU6052498A/en
Publication of WO1998034287A1 publication Critical patent/WO1998034287A1/fr
Publication of WO1998034287A9 publication Critical patent/WO1998034287A9/fr

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Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/80—Constructional details
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F17/00—Fixed inductances of the signal type 
    • H01F17/0006—Printed inductances
    • H01F17/0033—Printed inductances with the coil helically wound around a magnetic core

Definitions

  • This invention relates to microelectronics. It is specifically directed to inductive devices which are batch fabricated by the application of micromachining technology.
  • Inductors having a maximum linear turns density of approximately 15 turns/mm have been fabricated for high flux applications. Vias have been provided through plasma etching procedures, and conductors have been provided by electroplating. Inductors have also been fabricated by means of thick film technology.
  • U.S. Patent 3,614,554 discloses the fabrication of inductor coils with feed through holes (vias) through the use of thin film technology.
  • the metallic layers deposited by this means are necessarily of very thin cross section, and thus the current carrying coils are characterized by high resistance, while the magnetic cores are characterized by high reluctance.
  • the presence of vias contributes to both conductor resistance per turn and power loss.
  • This invention provides a novel inductive element, which may be constructed through batch fabrication techniques.
  • a typical fabrication process for realization of the inductor utilizes standard microelectronics materials and equipment.
  • the inductor may be fabricated by means of a post process utilizing micromachining technologies, rather than the thin film technologies conventional to integrated circuit fabrication.
  • Presently preferred fabrication procedures utilize relatively few, typically four, masks, and are completely compatible with, although distinguishable from, current integrated circuit fabrication technology.
  • the manufacturing process used to realize the integrated inductive components of the invention can be implemented to enhance or supplement foundry produced integrated circuits.
  • the process requires no high temperature processing steps or specialized equipment or materials.
  • the inductor of this invention is generic in character; variations on the manufacturing procedure in accordance with specific design requirements produce a corresponding variety of integrated magnetic components.
  • a planar substrate element serves as the structural base for the magnetic component of this invention.
  • the substrate element may comprise any of the materials commonly used for that purpose by the microelectronic industry, including without limitation, silicon, gallium arsenide, indium phosphide, and ceramics.
  • the substrate element may contain integrated circuit elements of systems with which a component fashioned in accordance with this invention is to be integrated.
  • an insulating layer is deposited on the substrate, and is patterned to open contact pads for connection from the magnetic component to any underlying circuitry.
  • a first (bottom) conductor is deposited and patterned in accordance with conventional photolithographic techniques.
  • the conductor may comprise any or a combination of conductive materials, typically low resistance metals. These metals may be deposited by means of sputtering, electron beam evaporation, filament evaporation, electro-deposition or other suitable techniques.
  • an insulating layer typically between about l ⁇ m to about 10 ⁇ m thick
  • any magnetic material that can be electroplated is a viable candidate for use in an inductor.
  • the core material selected for any specific device depends upon the characteristics of interest (e.g. high permeability, low losses at high frequencies).
  • the thickness of the electroplated metal is typically 1 ⁇ m to 50 ⁇ m.
  • insulating material usually within the range of about l ⁇ m to about 10 ⁇ m thick
  • This procedure is followed by deposition and patterning of a second (top) conductor.
  • the same materials are generally, but not necessarily, used for the top insulator and conductor as for the bottom insulator and conductor, respectively.
  • the entire structure may be encapsulated for protection from moisture.
  • a moisture resistant material is required.
  • Bio compatible encapsulation may be required to render the inductors suitable for use in conductive body fluids, for example.
  • Polyimide and parylene are examples of suitable encapsulating materials for most applications.
  • inductive elements of preferred embodiments provide a low reluctance core.
  • inductors of this invention may be incorporated in a variety of practical devices, notably, integrated inductors, integrated transformers, position sensors, telemetry systems and micromotors.
  • bar -type inductive elements are fashioned with metallic (ideally an electric grade aluminum alloy) conductors wrapped around a permalloy magnetic core. Connection between the upper and lower conductors of the device requires no vias. Therefore, losses due to series resistance through the wrapped conductor are minimized, and the heat generated by relatively large currents is also minimized.
  • the mutual flux produced by the primary (excitation) side should be maximized correspondingly to maximize the magnetization inductance of the transformer. With the magnetization inductance maximized, the behavior of the transformer more closely approximates that of an ideal transformer at high frequencies.
  • the device may be embodied as an isolation transformer for use in communication applications.
  • an inductor capable of integration into solid state integrated circuits may be fabricated in accordance with this invention by first selecting an appropriate substrate from those otherwise useful in the fabrication of integrated circuits (an "integrated circuit component substrate”.) A first conductive layer is then deposited atop the substrate, the first conductive layer being patterned to provide a first set of spaced conductor elements.
  • a first isolation layer is then deposited atop the first conductive layer, the first isolation layer being patterned to expose opposite ends of individual conductors of the first set of spaced conductor elements.
  • a magnetic core element may then be deposited atop the first isolation layer within the boundaries of the first set of spaced conductor elements.
  • a second isolation layer is deposited atop the magnetic core element, the second isolation layer being patterned to expose the opposite ends of individual conductors of the first set of spaced conductor elements.
  • a second conductive layer is then deposited atop the second isolation layer in contact with the opposite ends of the first set of spaced conductors, the second conductive layer being patterned to provide a second set of spaced conductor elements.
  • the conductors of the first and second sets of spaced conductor elements are inherently interconnected (as a consequence of patterning) to form primary and secondary coils around the core element.
  • a moisture barrier coating may be applied to surround an entire assembly comprising the first conductive layer, the first isolation layer, the core, the second isolation layer and the second conductive layer.
  • the magnetic core is most practically fabricated through micromachining technology, including the steps of depositing a metallic seed layer atop the first isolation layer, depositing a layer of photoresist over the seed layer, etching the photoresist to create a mold, the bottom of which is composed of the seed layer, electroplating the core within the mold atop the seed layer, and removing the excess portion of the photoresist layer and the seed layer.
  • Excess is meant all of the seed layer not covered by core material, and all of the photoresist layer not previously etched away during patterning.
  • the core is electroplated until it overflows the mold, whereby to achieve a shape characterized by an elliptical cross section. This elliptical section can be established as viewed from any or all coordinate axis directions.
  • FIGs. 1-4 are schematic illustrations of the steps of a fabrication process of the invention.
  • FIG. 5 is a perspective view of an inductive component of the invention
  • FIG. 6 is a sectional view taken along the reference line 6-6 of FIG. 5
  • FIG. 7 is a perspective view of a magnetic position sensor of the invention
  • FIG. 8 is a sectional view taken along the reference line 8-8 of FIG. 7.
  • a vialess inductive component, designated generally 26 is fabricated atop a suitable substrate 30.
  • a first conductive layer 32 is deposited on the substrate 30. (Although not shown, an isolation layer is often interposed between the substrate 30 and the first conductive layer.)
  • a first isolation layer 34 is deposited atop the first conductive layer, leaving end portions 36, 38 exposed.
  • a 0.1 ⁇ m thick layer of copper metal is deposited over the first isolation layer 34 to function as an electroplating seed layer 39.
  • a 0.5 ⁇ m photoresist layer 40 is deposited over the seed layer and terminal ends (FIG. 2), leaving an open portion (mold) 42 of the photoresist layer 40 to expose the electroplating seed layer 39.
  • a low reluctance magnetic core 50 is electroplated atop the isolation layer (FIG. 3). The photoresist 40 and seed 39 layers are then removed.
  • the magnetic core 50 material is allowed to "overplate” out of the mold 42.
  • This overplating allows for an elliptical cross-section, which is useful for obtaining coverage over the magnetic core 50 in subsequent steps.
  • overplating eliminates sharp corners in the magnetic core material.
  • a second isolation layer 52 is deposited over the core 50, followed by the deposition of a second conductive layer 54.
  • the entire assembly can then be encapsulated with suitable protective material 56.
  • the basic inductive device is shown embodied as a transformer.
  • the conductive layers 32, 54 are of aluminum and are patterned cooperatively as primary 60 and secondary 62 coils, characterized by high turns density.
  • the isolation layers 34, 52 are of polyimide insulation material.
  • the performance of a 1 : 1 transformer of similar construction has been characterized. The efficiency of the device tested was approximately 85 % . This efficiency can be increased by reducing the winding resistance of the current carrying coil.
  • Such a reduction can be effected by either or both increasing the cross-sectional area of the conductor and decreasing the contact resistance between the upper and lower conductors of the device.
  • the device has been operated up to 10 MHz with minimal changes in characteristics due to high frequency losses. This performance is attributable to: 1) the correct choice of magnetic core materials, 2) the large cross sectional area of the core, and 3) the elimination of sharp corners due to the elliptical design of the core.
  • the maximum turns density of the devices is 100 turns/mm.
  • the resistance of the coils is less than 1.0 ohms per turn at 500 mA of current.
  • the inductive component 26 may alternatively be embodied as a magnetic position sensor, as illustrated by FIGs. 7 and 8.
  • the structure is similar to that depicted by FIGs. 5 and 6, except that the core 70 is shorter than the tunnel 72 provided by the isolation layers 34, 52. Moreover, the core 70 is reciprocally mounted within the tunnel between blocks 74, 76 of non-magnetic shielding material. Longitudinal movement of the core 70 within the tunnel 72 causes detectable changes in the current and/or voltage detected in the secondary coil 62.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Coils Or Transformers For Communication (AREA)
  • Semiconductor Integrated Circuits (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)
  • Burglar Alarm Systems (AREA)

Abstract

La présente invention a trait à un inducteur que l'on peut intégrer dans des circuits et des dispositifs VLSI. Cet inducteur est fabriqué selon un procédé postfonderie de dépôt et de formation de couches de matériau conducteur (32), de matériau isolant (34), de matériau noyau (50), de matériau isolant (52) et de matériau conducteur (54) de façon à produire des bobines conductrices (60, 62) enveloppées autour d'un noyau magnétique, sans qu'il y ait besoin de trous d'interconnexions. Les étapes de fabrication combinent les techniques du microusinage et de la microéléctronique.
PCT/US1998/001879 1997-02-03 1998-01-30 Elements inductifs integres sans trous d'interconnexions pour des applications electromagnetiques WO1998034287A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP53314298A JP2002513511A (ja) 1997-02-03 1998-01-30 電磁気応用のためのヴァイアの無い集積誘導性素子
CA002279297A CA2279297A1 (fr) 1997-02-03 1998-01-30 Elements inductifs integres sans trous d'interconnexions pour des applications electromagnetiques
EP98903872A EP1000442A4 (fr) 1997-02-03 1998-01-30 Elements inductifs integres sans trous d'interconnexions pour des applications electromagnetiques
AU60524/98A AU6052498A (en) 1997-02-03 1998-01-30 Vialess integrated inductive elements for electromagnetic applications

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US79433897A 1997-02-03 1997-02-03
US08/794,338 1997-02-03

Publications (2)

Publication Number Publication Date
WO1998034287A1 true WO1998034287A1 (fr) 1998-08-06
WO1998034287A9 WO1998034287A9 (fr) 1998-12-10

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PCT/US1998/001879 WO1998034287A1 (fr) 1997-02-03 1998-01-30 Elements inductifs integres sans trous d'interconnexions pour des applications electromagnetiques

Country Status (7)

Country Link
EP (1) EP1000442A4 (fr)
JP (1) JP2002513511A (fr)
KR (1) KR20000070732A (fr)
AU (1) AU6052498A (fr)
CA (1) CA2279297A1 (fr)
TW (1) TW362287B (fr)
WO (1) WO1998034287A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007072375A2 (fr) * 2005-12-22 2007-06-28 Koninklijke Philips Electronics N.V. Procede de fabrication d'un composant microelectronique, au moins un enroulement electriquement conducteur etant dispose autour d'un element de noyau en ferrite

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108426380A (zh) * 2018-03-13 2018-08-21 桑夏太阳能股份有限公司 一种新型太阳能光伏光热复合集热器
WO2019220862A1 (fr) * 2018-05-18 2019-11-21 株式会社村田製作所 Inducteur et son procédé de production

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3614554A (en) * 1968-10-24 1971-10-19 Texas Instruments Inc Miniaturized thin film inductors for use in integrated circuits
US3858138A (en) * 1973-03-05 1974-12-31 Rca Corp Tuneable thin film inductor
US4082916A (en) * 1976-12-16 1978-04-04 Westinghouse Electric Corporation Encapsulated electrical inductive apparatus
US4600911A (en) * 1984-03-20 1986-07-15 Pauwels-Trafo Belgium N.V. Elliptically shaped magnetic core
US4848684A (en) * 1986-11-22 1989-07-18 Kitamura Kiden Co., Ltd. Wound core having circular and elliptic outer surface portions
US5070317A (en) * 1989-01-17 1991-12-03 Bhagat Jayant K Miniature inductor for integrated circuits and devices
US5279988A (en) * 1992-03-31 1994-01-18 Irfan Saadat Process for making microcomponents integrated circuits

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3881244A (en) * 1972-06-02 1975-05-06 Texas Instruments Inc Method of making a solid state inductor
JPH05166623A (ja) * 1991-12-12 1993-07-02 Matsushita Electric Ind Co Ltd 小形固定コイル

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3614554A (en) * 1968-10-24 1971-10-19 Texas Instruments Inc Miniaturized thin film inductors for use in integrated circuits
US3858138A (en) * 1973-03-05 1974-12-31 Rca Corp Tuneable thin film inductor
US4082916A (en) * 1976-12-16 1978-04-04 Westinghouse Electric Corporation Encapsulated electrical inductive apparatus
US4600911A (en) * 1984-03-20 1986-07-15 Pauwels-Trafo Belgium N.V. Elliptically shaped magnetic core
US4848684A (en) * 1986-11-22 1989-07-18 Kitamura Kiden Co., Ltd. Wound core having circular and elliptic outer surface portions
US5070317A (en) * 1989-01-17 1991-12-03 Bhagat Jayant K Miniature inductor for integrated circuits and devices
US5279988A (en) * 1992-03-31 1994-01-18 Irfan Saadat Process for making microcomponents integrated circuits

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP1000442A4 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007072375A2 (fr) * 2005-12-22 2007-06-28 Koninklijke Philips Electronics N.V. Procede de fabrication d'un composant microelectronique, au moins un enroulement electriquement conducteur etant dispose autour d'un element de noyau en ferrite
WO2007072375A3 (fr) * 2005-12-22 2007-11-01 Koninkl Philips Electronics Nv Procede de fabrication d'un composant microelectronique, au moins un enroulement electriquement conducteur etant dispose autour d'un element de noyau en ferrite

Also Published As

Publication number Publication date
KR20000070732A (ko) 2000-11-25
CA2279297A1 (fr) 1998-08-06
EP1000442A1 (fr) 2000-05-17
AU6052498A (en) 1998-08-25
JP2002513511A (ja) 2002-05-08
TW362287B (en) 1999-06-21
EP1000442A4 (fr) 2000-05-17

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