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Publication numberUS3858138 A
Publication typeGrant
Publication dateDec 31, 1974
Filing dateMay 10, 1974
Priority dateMar 5, 1973
Publication numberUS 3858138 A, US 3858138A, US-A-3858138, US3858138 A, US3858138A
InventorsJ Gittleman, L Zappulla
Original AssigneeRca Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Tuneable thin film inductor
US 3858138 A
Abstract
A flat inductor, one half of which is provided as a first set of parallel conductive strips printed on a substrate, each of which constitutes one half of each turn of a helix. A flat sleeve of insulating material is adherently disposed over the substrate strips leaving the ends of the strips exposed. The other half of the helix is provided as a second set of parallel conductive strips printed on the sleeve with the ends of the second set of strips contacting the exposed ends of the first set. A flat strip-like magnetic core member is slidably disposed within the sleeve.
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United States Patent 1191 Gittleman et a1.

[ Dec. 31, 1974 [5 TUNEABLE THIN FILM INDUCTOR 3,344,237 9/1967 Gregg 336/200 x 3,413,716 12/1968 Schwertz et al. 336/200 X [751 Inventors: Isaac Trenton; 3,614,554 10/1971 Richardson 336/200 x Lawrence Matthew Zappulla, 3,638,156 1/1972 West 336/200 l-lazlet, both of NJ. 3,731,005 5/1973 Shearman 336/200 X 73 A RCA C t N Y k, N.Y. sslgnee orpom ew or Primary Examiner-Thomas J. Kozma Flledi y 1 1974 Attorney, Agent, or FirmG. H. Bruestle; W. S. Hill; 211 App]. No.2 468,932 Van Tmht Related U-S. Application Data [63] 552252225 of 338l March 1973 A flat inductor, one half of which is provided as a first set of parallel conductive strips printed on a substrate, each of which constitutes one half of each turn of a 2 helix. A flat sleeve of insulating material is adherently I disposed Over the substrate Strips leaving the ends of [58] Fleld of Search 336/136, 200, 223 the strips exposed The other half of the helix is p vided as a second set of parallel conductive strips [56] References Cited printed on the sleeve with the ends of the second set UNITED STATES PATENTS of strips contacting the exposed ends of the first set. A 2,989,630 6/1961 Crooker 336/200 X flat stripdike magnetic core member is slidably dis- 3,000,079 9/ 1961 Howell et a1 336/200 X posed within the Sleeve 3,210,707 10/1965 Constantakes.... 336/200 3,305,814 2/ 1967 Moyer 336/200 5 Cl lms, 8 Drawing Flgures I2 6 8 40 4b 4c 4d 4e /--5 1 1 I l l A 3 r\-- h 1 3.

ll I I l I l8 7 101 101 10 101 #5 106 16 TUNEABLE THIN FILM INDUCTOR This is a continuation of application Ser. No. 338,1 l0, filed Mar. 5, 1973 now abandoned.

The invention herein described was made in the course of or under Contract 5882(25-313/71 )71R.

BACKGROUND OF THE INVENTION This invention is an inductor intended for use in miniaturized integrated circuits, especially circuits of the so-called hybrid type wherein conductors and some passive elements are printed or otherwise deposited on an insulating substrate. Active circuit elements and, usually, some passive elements, are separately fabricated, and attached to the substrate conductors by $01- dering. In this type of circuit, inductors have been a particular problem although several different types of inductors have been proposed. One type has been simply a flat spiral of conducting material. Fairly high inductances can be achieved with this type of inductor but at the expense of using up a relatively large area of substrate.

Another type of inductor proposed for miniature circuits is a flat helix with a flat bar of magnetic material for the core. This type provides higher inductances than the dielectric core type described above. An example of this type of inductor is described in US. Pat. No. 3,614,554 to Richardson et a]. It has been recog nized that it would be desirable to be able to tune this type of inductor but heretofore no method has been proposed for making a tuneable inductor of this type.

The present invention provides a film type inductor which is tuneable because it includes a moveable magnetic core.

THE DRAWING FIG. 1 is a plan view of an inductor of the present invention;

FIGS. 2-7 are similar views illustrating successive steps in making the device of FIG. 1; and FIG. 8 is a cross section view taken along the line 8-8 of FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENT As shown in FIG. 1, an embodiment of an inductor in accordance with the present invention may comprise an insulating substrate 2 on which is a first series of parallel metal film stripes 4a-4e. Covering all of these stripes except the ends thereof is a first film 6 of insulating material. On top of the first insulating film 6 is a second film of insulating material 8 which, at least along its central portion, is not joined to the first film 6. Together, these two films of material constitute a sleeve. There is a narrow space available between the two films 6 and 8 when the films are flexed. On top of the second film of insulating material 8 is a second se ries of parallel metal film stripes la-10e disposed at an angle to the stripes of the first series. Each of these stripes except 10a is joined to two of the lower series of stripes 4a-4d at the ends of the stripes. Stripes 4e and 10a are each joined to only one stripe in the opposite series because of their end positions in the series. The two series of metal stripes 4a4e and l0a-10e together constitute a flat helix. The stripes in each series do not need to be parallel to each other but the parallel arrangement is preferred.

Moveably disposed between the insulating films 6 and 8 is a core 11 composed of a strip of insulating material 12 having coatings of magnetic material 14 on both faces. The strip 12 may be moved to any desired position within the helix to vary the inductance of the device.

In order to connect the device in circuit, end metal stripe re is joined to a bonding pad 16 and end metal stripe 10a is joined to a bonding pad 18.

An example of a method of making an inductor of the present invention will now be given.

The substrate 2 may comprise a suitably sized ceramic or glass plate. In order to make the bottom series of metal stripes 4a-4e (FIG. 2), a thin film of gold may be deposited by evaporation or electroless deposition over the entire top surface of the substrate and the stripes may be delineated by conventional photoprocessing and etching techniques. Alternatively, a removable mask may be applied to the substrate and metal may be deposited only where the stripes are to be formed. Other suitable metals, such as copper, may also be used instead of gold. The thickness, pitch and width of the stripes are chosen to be consistent with the required number of turns of the completed coil and to maximize the coil Q.

Next (FIG. 3), the first film of insulating material 6 is desposited on the substrate 2 and over the stripes 4a-4e except over the ends thereof. The film may have a thickness of about 10 microns and may be composed of a synthetic resin such as polyimide. An example of a commercially available polyimide is Pyralin 5077" a product of E. I. Du Pont de Nemours. The film 6 can be deposited deposited by screen printing techniques or by using a stencil.

In order to fabricate the top insulating film 8 so that at least the central portion will not be adherent to the lower film 6, a mandrel 20 (FIG. 4), having dimensions such that it covers the central portion of film 6 over its entire length, is placed over the film 6. The mandrel may be made of a non-adherent material such as Teflon and may be 1 mil thick, for example, or it may be made of a metal such as copper or aluminum which can later be removed by etching.

The second film of insulating material 8 (FIG. 5), having the same dimensions as the first film 6, is then deposited over the mandrel 20 and over the edge portions of the film 6. The second film 8 adheres to the first film 6 along its edges but not, of course, where the film 6 is covered by the mandrel 20.

Next, the second series of metal film stripes 10a-10e (FIG. 6), is deposited over the second insulating film 8. These stripes are disposed at an angle such that their ends are joined to the ends of the first series of metal stripes 4a4e. That is, stripe 10a is joined to stripe 4a, stripe 10b is joined to stripes 4a and 4b, etc. This combination of metal stripes forms a flat helix.

At the completion of fabrication, the mandrel 20 is removed and a moveable core 11 is slipped between sired in the sputtered film, pressing the resultant mixture in the'shape of a disc target, and firing the disc at an elevated temperature, e.g., 1,100 C, for about an hour in a hydrogen atmosphere. For example, the mixture may consist of (in parts by weight) 1.0 part iron, 0.531 part nickel and 0.336 part silica. This mixture may be pressed at 12,000 psi into a disc 6 inches in diameter and about A inch thick.

A film sputtered from the above disc has the composition (Fe Ni (SiO in parts by volume. The permeability of the film is 150 and resistivity is 9 X 10 ohm-cm.

If a substrate is used which is heat-resistant, the film can be annealed to increase permeability.lf annealed at 250 C for 2 hours under vacuum and then cooled to room temperature, for example, the permeability increases to 270 and resistivity rises to 1.1 X 10 ohmif a magnetic film of variable composition is desired, a disc shaped target can be prepared by fabricating it of three different sectors, one sector containing iron, a second sector containing nickel and a third sector containing silica.

The magnetic film 14 can also be of constant composition but of variable thickness by exposing different portions of the substrate to the sputtering operation for different lengths of time.

The magnitude of the inductance for the present inductor configuration is given by the equation:

L 1.261O N (d, ad where L is in nanohenries, N is the number of turns, d, is the total insulation thickness of the films 6 and 8 and the Mylar strip 12, d is the thickness of the ferromagnetic coating of the core 11 and p. is the permeability. Thicknesses are in microns.

As an example, if N 20 turns, total insultion thickness of the films and core substrate is 40 microns, u 150 and the thickness of the magnetic coating on the core is 5 microns, a maximum inductance can be obtained as follows:

L= 1.26 X X 400 X (40 +150 X 5) The inductor is provided with terminals for connecting it in circuit by depositing on-the substrate 2 a metal pad 16 overlapping the free end of the stripe 4e and another metal pad 18 overlapping the free end of the stripe 10a. 8

We claim:

1. A tuneable film type inductor comprising a first series of metal film stripes adhered to an insulating substrate, a first synthetic resinous film of insulating material covering said stripes except the ends thereof, a second synthetic resinous film of insulating material over said first film and having a central portion spaced therefrom, both of said films being joined along their edges such that both films together form a sleeve, a second series of metal film stripes on top of said second film of insulating material, each member of said second series of strips being connected to members of said first series of stripes to form a continuous flat helix, and a moveable member of magnetic material disposed between said insulating films, said moveable member comprising a thin strip of dielectric material with a coating of ferromagnetic material thereon.

2. An inductor according to claiml in which said ferromaganetic layer is a sputtered layer.

3. An inductor according to claim 1 in which said coating of ferromagnetic material is of variable composition.

4. An inductor according to claim 1 in which said coating of ferromagnetic material is of variable thickness.

5. An inductor according to claim 1 in which said coating of ferromagnetic material is on both sides of said strip.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2989630 *Oct 14, 1957Jun 20, 1961Motorola IncTuning apparatus
US3000079 *May 5, 1955Sep 19, 1961Aladdin Ind IncTuner and method for making same
US3210707 *Oct 4, 1962Oct 5, 1965Gen Instrument CorpSolid state inductor built up of multiple thin films
US3305814 *Aug 7, 1963Feb 21, 1967 Hybrid solid state device
US3344237 *Apr 19, 1961Sep 26, 1967 Desposited film transducing apparatus and method op producing the apparatus
US3413716 *Apr 30, 1965Dec 3, 1968Xerox CorpThin-film inductor elements
US3614554 *Oct 24, 1968Oct 19, 1971Texas Instruments IncMiniaturized thin film inductors for use in integrated circuits
US3638156 *Dec 16, 1970Jan 25, 1972Laurice J WestMicroinductor device
US3731005 *May 18, 1971May 1, 1973Metalized Ceramics CorpLaminated coil
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4522671 *Nov 12, 1982Jun 11, 1985Robert Bosch GmbhMethod of applying an electrical conductor pattern on an apertured substrate
US4649755 *Dec 24, 1984Mar 17, 1987International Standard Electric CorporationSensor for magnetizable materials
US4782705 *Jul 10, 1987Nov 8, 1988Alcatel N.V.Strain gauge
US4890084 *May 12, 1988Dec 26, 1989The Institute Of Rock & Soil Mechanics Academia SinicaInductance strain gauge
US5392020 *Dec 14, 1992Feb 21, 1995Chang; Kern K. N.Flexible transformer apparatus particularly adapted for high voltage operation
US6278353 *Nov 16, 1999Aug 21, 2001Hamilton Sundstrand CorporationPlanar magnetics with integrated cooling
US6329892 *Jan 20, 2000Dec 11, 2001Credence Systems CorporationLow profile, current-driven relay for integrated circuit tester
US6367143 *Mar 5, 1999Apr 9, 2002Smart Card Technologies Co. Ltd.Coil element and method for manufacturing thereof
US6369683 *Feb 1, 2000Apr 9, 2002Murata Manufacturing Co., LtdVariable inductor
US6456183Feb 24, 2000Sep 24, 2002Memscap And Planhead-Silmag PhsInductor for integrated circuit
US6480084 *Jun 29, 2000Nov 12, 2002Kabushiki Kaisha ToshibaInductance element and manufacturing method thereof, and snubber using thereof
US6600403 *Dec 1, 1995Jul 29, 2003Koninklijke Philips Electronics N.V.Planar inductor
US6628188 *Feb 19, 2002Sep 30, 2003Murata Manufacturing Co., Ltd.Variable inductor and method
US6722017Apr 10, 2003Apr 20, 2004Koninklijke Philips Electronics N.V.Planar inductor
US6838970Jul 26, 2002Jan 4, 2005MemscapInductor for integrated circuit
US7167073 *Oct 20, 2004Jan 23, 2007Rohm Co., Ltd.Semiconductor device
US7229908 *Jun 4, 2004Jun 12, 2007National Semiconductor CorporationSystem and method for manufacturing an out of plane integrated circuit inductor
US7368908 *Jul 26, 2006May 6, 2008Sumida CorporationMagnetic element
US7511351 *Jul 27, 2005Mar 31, 2009Oki Electric Industry Co., Ltd.Semiconductor device and method for fabricating the same
US7868431Jan 11, 2011Alpha And Omega Semiconductor IncorporatedCompact power semiconductor package and method with stacked inductor and integrated circuit die
US7884452Nov 23, 2007Feb 8, 2011Alpha And Omega Semiconductor IncorporatedSemiconductor power device package having a lead frame-based integrated inductor
US7884696 *Feb 8, 2011Alpha And Omega Semiconductor IncorporatedLead frame-based discrete power inductor
US8058961Nov 15, 2011Alpha And Omega Semiconductor IncorporatedLead frame-based discrete power inductor
US8115571 *Nov 28, 2008Feb 14, 2012Schaffner Emv AgHarmonic filter
US8217748Jul 10, 2012Alpha & Omega Semiconductor Inc.Compact inductive power electronics package
US20040004525 *Apr 10, 2003Jan 8, 2004Ulrich RittnerPlanar inductor
US20050088269 *Oct 20, 2004Apr 28, 2005Rohm Company, Ltd.Semiconductor device
US20050156703 *Jan 20, 2004Jul 21, 2005Mark TwaalfhovenMagnetic toroid connector
US20050263847 *Jul 27, 2005Dec 1, 2005Noritaka AnzaiSemiconductor device and method for fabricating the same
US20070024279 *Jul 26, 2006Feb 1, 2007Sumida CorporationMagnetic element
US20070241848 *Apr 13, 2007Oct 18, 2007Sumida CorporationMagnetic element
US20080309446 *Jun 6, 2006Dec 18, 2008Wulf GuentherArrangement Comprising an Inductive Component
US20090134964 *Jan 25, 2008May 28, 2009Francois HebertLead frame-based discrete power inductor
US20090160595 *Feb 23, 2009Jun 25, 2009Tao FengCompact Power Semiconductor Package and Method with Stacked Inductor and Integrated Circuit Die
US20090167477 *Mar 4, 2009Jul 2, 2009Tao FengCompact Inductive Power Electronics Package
US20100134204 *Nov 28, 2008Jun 3, 2010Schaffner Emv AgHarmonic filter
US20110121934 *May 26, 2011Hebert FrancoisLead Frame-based Discrete Power Inductor
US20120133473 *May 31, 2012Hon Hai Precision Industry Co., Ltd.Inductive component having terminal winding
US20140191829 *Mar 12, 2014Jul 10, 2014Fujikura Ltd.Coil wiring element and method of manufacturing coil wiring element
CN100573754CJul 18, 2006Dec 23, 2009胜美达集团株式会社Magnetic element
CN101902044B *Nov 27, 2009May 6, 2015沙夫纳Emv股份公司谐波滤波器
CN103975398A *Aug 20, 2012Aug 6, 2014温彻斯特技术有限责任公司Electrostatically tunable magnetoelectric inductors with large inductance tunability
DE3036704A1 *Sep 29, 1980May 13, 1982Siemens AgHybrid coil for use as frequency filter in PCM telephony - uses variable reluctance magnetic core inserted between two insulation layers
DE3039113A1 *Oct 16, 1980May 13, 1982Siemens AgVariable inductance coil for telephone network - has short-circuit strap between several fragments or between several sections
DE3039163A1 *Oct 16, 1980May 13, 1982Siemens AgVariable inductance coil for telephone network - has fragments and sections to form network having at least one separate loop
DE4306416A1 *Mar 2, 1993Sep 8, 1994Kolbe & Co HansCoil structure for a printed circuit board arrangement
EP0134556A1 *Aug 14, 1984Mar 20, 1985TDK CorporationAn impedance element
EP0942441A2 *Mar 9, 1999Sep 15, 1999Smart Card Technologies Co., Ltd.Coil element and method for manufacturing thereof
EP1032001A1 *Feb 22, 2000Aug 30, 2000MemscapInductive component, integrated transformer, in particular for a radio frequency circuit, and associated integrated circuit with such inductive component or integrated transformer
EP1845538A2 *Apr 5, 2007Oct 17, 2007Sumida CorporationMagnetic element
WO1994014174A1 *Dec 8, 1993Jun 23, 1994Chang Kern K NFlexible transformer apparatus particularly adapted for high voltage operation
WO1997018570A1 *Nov 14, 1996May 22, 1997Daewoo Electronics Co., Ltd.Cylindrical coil winding structure of flyback transformer
WO1997020329A1 *Nov 30, 1996Jun 5, 1997Daewoo Electronics Co., Ltd.Flexible coil winding structure of flyback transformer and manufacturing process thereof
WO1997020330A1 *Nov 30, 1996Jun 5, 1997Daewoo Electronics Co., Ltd.Flexible coil winding structure of flyback transformer and manufacturing process thereof
WO1998034287A1 *Jan 30, 1998Aug 6, 1998University Of Utah Research FoundationVialess integrated inductive elements for electromagnetic applications
WO2013026056A1 *Aug 20, 2012Feb 21, 2013Northeastern UniversityElectrostatically tunable magnetoelectric inductors with large inductance tunability
Classifications
U.S. Classification336/136, 336/200
International ClassificationH01F27/24, H01F17/00
Cooperative ClassificationH01F27/24, H01F21/06, H01F2017/0066
European ClassificationH01F21/06, H01F27/24