I 1111111111111111 11111 111111111111111 IIIII IIIII 11111 111111111111111 IIII IIII
`US008164001B2
`
`c12) United States Patent
`Yoshida et al.
`
`(IO) Patent No.:
`(45) Date of Patent:
`
`US 8,164,001 B2
`Apr. 24, 2012
`
`(54) MULTILAYER PRINTED CIRCUIT BOARD
`
`(75)
`
`Inventors: Shigeyoshi Yoshida, Sendai (JP); Koichi
`Kondo, Sendai (JP); Hiroshi Ono,
`Sendai (JP); SatoshiArai, Sendai (JP);
`Tadashi Kubodera, Ebina (JP)
`
`(73) Assignee: NEC Tokin Corporation, Sendai-Shi
`(JP)
`
`( *) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 1147 days.
`
`CN
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`WO
`
`FOREIGN PATENT DOCUMENTS
`1476292 A
`2/2004
`7-142249 A
`6/1995
`2004-056144 A
`2/2004
`2004-111956 A
`4/2004
`2005-032969 A
`2/2005
`2005-129766 A
`5/2005
`2006-019590 A
`1/2006
`2006-100608 A
`4/2006
`2006-108557 A
`4/2006
`2006-210616 A
`8/2006
`2006-294769 A
`10/2006
`03/015109 Al
`2/2003
`
`OTHER PUBLICATIONS
`
`(21) Appl. No.: 11/986,432
`
`(22) Filed:
`
`Nov. 21, 2007
`
`(65)
`
`Prior Publication Data
`
`US 2009/0047507 Al
`
`Feb. 19, 2009
`
`(30)
`
`Foreign Application Priority Data
`
`Nov. 22, 2006
`Jul. 24, 2007
`Aug. 27, 2007
`
`(JP) ................................. 2006-316209
`(JP) ................................. 2007-191929
`(JP) ................................. 2007-219541
`
`(51)
`
`Int. Cl.
`HOSK 1103
`(2006.01)
`(52) U.S. Cl. ........................................ 174/255; 174/259
`(58) Field of Classification Search ........... 174/255-259
`See application file for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`5,695,877 A *
`12/1997 Davis ............................ 428/329
`6,075,211 A *
`6/2000 Tohya et al.
`174/255
`7,108,799 B2 *
`9/2006 Kobayashi et al.
`........ 252/62.62
`2004/0012935 Al
`1/2004 Tagi et al.
`2004/0124941 Al*
`7/2004 Awakura et al. ................ 333/12
`2004/0238796 Al
`12/2004 Abe
`
`Chinese Office Action dated Sep. 11, 2009 and English translation
`thereof
`issued
`in a counterpart Chinese Application No.
`2007101864985.
`Japanese Office Action dated Dec. 8, 2011 ( and English translation
`thereof) in counterpart Japanese Application No. 2007-219541.
`
`* cited by examiner
`
`Primary Examiner -
`Jeremy Norris
`(74) Attorney, Agent, or Firm -Holtz, Holtz, Goodman &
`Chick, PC
`
`ABSTRACT
`(57)
`A multilayer printed circuit board includes an inner magnetic
`layer essentially consisting of magnetic material. The inner
`magnetic layer may be formed by an action of chemical bond
`or van der Waals force. The inner magnetic layer may com(cid:173)
`prise a plurality of magnetic units, each of which provides
`magnetism, and may be formed by magnetically coupling the
`magnetic units with each other by using a strong interaction.
`The inner magnetic layer may essentially consist of a ferrite
`film. The ferrite film may be formed directly on the inner
`conductive layer by means of an electro less plating method.
`The ferrite film may essentially consist of an oxide metal
`composition, the metal composition being represented by the
`formula
`a+b+c+d=3.0;
`of FeaNi6ZncCod, where:
`2.l~a~2.7; 0.l~b~0.3; 0.l~c~0.7; and0~d~0.15.
`
`2 Claims, 9 Drawing Sheets
`
`451
`
`llrt:"T't-431
`"'-'-''-'-"-«r--421
`
`441
`
`470{!~:
`472
`410
`461
`
`bl
`
`442
`
`1177:.,,-r,,;i-..422
`H!;.°S:~lli:S~i---432
`
`452
`
`Ex.1014
`APPLE INC. / Page 1 of 16
`
`

`

`U.S. Patent
`
`Apr. 24, 2012
`
`Sheet 1 of 9
`
`US 8,164,001 B2
`
`COLUMNAR CRYSTAL
`
`3µm
`
`f
`l
`
`MAGNETOSTATIC COUPLING
`
`EXCHANGE COUPLING
`
`FIG. 1
`
`60 r-------r===========
`--FERRITE-PLATED FILM
`50
`- - - - - COMPOS I TE MAGNET I G SHEE
`
`40
`
`30
`
`20
`
`·10
`
`0
`
`,
`
`...
`
`----~
`
`I
`,
`I
`
`'
`
`'
`
`'
`
`'
`
`' ... ...
`
`...
`
`'
`
`1
`
`10
`
`100
`
`1000
`
`10000
`
`Frequency
`
`(MHz)
`
`FIG.2
`
`Ex.1014
`APPLE INC. / Page 2 of 16
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`

`

`U.S. Patent
`
`Apr. 24, 2012
`
`Sheet 2 of 9
`
`US 8,164,001 B2
`
`103
`
`103
`
`105
`
`106
`
`102
`
`107
`
`FIG.3A
`
`107
`
`103
`
`103 103
`
`Gly]N ~N
`
`104
`
`104
`
`FIG.3B
`
`Ex.1014
`APPLE INC. / Page 3 of 16
`
`

`

`U.S. Patent
`
`Apr. 24, 2012
`
`Sheet 3 of 9
`
`US 8,164,001 B2
`
`203
`
`,------------------------
`,
`,
`,
`,
`,
`;
`
`;
`
`/
`
`,
`,
`
`201
`
`202
`
`FIG.4
`
`Ex.1014
`APPLE INC. / Page 4 of 16
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`

`

`U.S. Patent
`
`Apr. 24, 2012
`
`Sheet 4 of 9
`
`US 8,164,001 B2
`
`351
`
`341
`
`.........,.......-.r-~llrr-c~~~1-....-331
`321
`
`310
`
`al
`
`i--A----4~~-•••,••ll!J1""r.7"7""7-:i-._322
`332
`
`342
`
`352
`
`FIG.5
`
`Ex.1014
`APPLE INC. / Page 5 of 16
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`

`

`U.S. Patent
`
`Apr. 24, 2012
`
`Sheet 5 of 9
`
`US 8,164,001 B2
`
`451
`
`431
`421
`
`462
`
`b1
`
`441
`
`474
`470 476
`472
`
`410
`
`461
`
`442
`
`FIG.6
`
`Ex.1014
`APPLE INC. / Page 6 of 16
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`

`

`U.S. Patent
`
`Apr. 24, 2012
`
`Sheet 6 of 9
`
`US 8,164,001 B2
`
`c1
`
`541
`
`~~~ ~~M'l~~~-531
`i,...;a,.~-"( ]Ip,'~..,.,, ~.,---~--521
`
`563
`
`510
`
`t--+-~~l~._....m..1 .h'°"'~~--522
`532
`
`c2
`
`542
`
`FIG. 7
`
`Ex.1014
`APPLE INC. / Page 7 of 16
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`

`

`U.S. Patent
`
`Apr. 24, 2012
`
`Sheet 7 of 9
`
`US 8,164,001 B2
`
`(l)
`
`> Cl)
`
`_J
`
`20'-------'-----'---->--_.____.__..__,
`8000.0
`1000.0
`3000.0
`5000.0
`Frequency [MHz]
`
`FIG.8
`
`50
`
`40
`
`,....,
`'e'
`
`'--> ::s. -cO
`
`.......
`"'O
`
`(l)
`
`> Cl)
`~
`
`30
`
`20-------......_ __ --.J.__ _ _._ _ _.__....____.___,
`5000.0
`1000.0
`8000.0
`3000.0
`Frequency [MHz]
`FIG. 9
`
`Ex.1014
`APPLE INC. / Page 8 of 16
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`

`

`U.S. Patent
`
`Apr. 24, 2012
`
`Sheet 8 of 9
`
`US 8,164,001 B2
`
`,..., 50
`s'
`;;:-
`
`~ --
`
`co
`~
`
`40
`
`Q)
`>
`Q)
`....J
`
`30
`
`20L--_____ ......._ ___ ._ _ _._ ______ __.____.
`
`1000. 0
`
`5000. 0
`
`8000. 0
`
`3000. 0
`Frequency [MHz]
`
`FIG. 10
`
`,...., 50
`.-
`E
`~
`
`:::::t - 40
`
`m
`._,
`""O
`
`4)
`
`>
`Q,) _,
`
`30
`
`20.__ _______________ _
`
`1000. 0
`
`5000. 0
`
`8000. 0
`
`3000. 0
`Frequency [MHz]
`
`FIG. 11
`
`Ex.1014
`APPLE INC. / Page 9 of 16
`
`

`

`U.S. Patent
`
`Apr. 24, 2012
`
`Sheet 9 of 9
`
`US 8,164,001 B2
`
`~ --"->
`
`~ ......
`a:l
`.__.
`"'C
`
`Cl)
`:;,,
`G)
`...J
`
`50
`
`40
`
`30
`
`20'--------------__._ _ _.__,.____.,__.
`3000.0
`1000.0
`5000.0
`8000.0
`Frequency [MHz]
`
`FIG. 12
`
`,--,
`
`e ---...
`>
`:::s..
`.....,
`co
`.......
`"'Q
`
`Q)
`
`> Cl)
`
`_J
`
`50
`
`40
`
`30
`
`20------___,__ ___ ___._ _____________ __,
`3000.0
`1000.0
`5000.0
`8000.0
`Frequency [MHz]
`
`FIG. 13
`
`Ex.1014
`APPLE INC. / Page 10 of 16
`
`

`

`US 8,164,001 B2
`
`1
`MULTILAYER PRINTED CIRCUIT BOARD
`
`BACKGROUND OF THE INVENTION
`
`This invention relates to a printed circuit board on which an
`electronic component such as a semiconductor element is
`mounted. In particular, the present invention relates to a mul(cid:173)
`tilayer printed circuit board.
`In a recent electronic device having a multilayer printed
`circuit board and an electronic component mounted thereon, 10
`a high-frequency current flows into a power-supply layer or a
`ground layer of the multilayer printed circuit board because
`of various reasons. For example, electromagnetic coupling
`between a power-supply layer and a signal layer causes a
`high-frequency current to flow into the power-supply layer. A
`weakened ground layer causes a high-frequency current to
`flow into the ground layer. A length of a return-current path
`also influences a high-frequency current flowing into the
`ground layer. The flow of the high-frequency current into the
`power-supply layer or the ground layer constitutes a large
`current-loop which may cause a noise radiation problem.
`Since such noise is radiated from an inner layer of a mul(cid:173)
`tilayer printed circuit board, a noise suppression sheet stuck
`on an outer surface of the multilayer printed circuit board has
`little effect on reduction of the noise.
`JP-A 2006-100608 or JP-A 2006-019590 discloses a pre(cid:173)
`impregnation sheet that is, at least in part, formed of magnetic
`material, those documents being incorporated herein by ref(cid:173)
`erence. A multilayer printed circuit board formed of the pre(cid:173)
`impregnation material can suppress the above-mentioned
`noise radiated from the inside thereof. However, in order to
`obtain desirable noise suppression property in practical use,
`the pre-impregnation material with the magnetic material
`becomes very thicker. The thicker pre-impregnation material
`results in a larger multilayer printed circuit board larger.
`Therefore, there is a need for a new structure that can suppress
`the above-mentioned noise with small size.
`
`20
`
`SUMMARY OF THE INVENTION
`
`According to one aspect of the present invention, a multi(cid:173)
`layer printed circuit board includes an inner magnetic layer
`essentially consisting of magnetic material. The inner mag(cid:173)
`netic layer may be formed by an action of chemical bond or
`van der Waals force. The inner magnetic layer may comprise
`a plurality of magnetic units, each of which provides magne- 45
`tism, and may be formed by magnetically coupling the mag(cid:173)
`netic units with each other by using a strong interaction. The
`inner magnetic layer may essentially consist of a ferrite film.
`The ferrite film may be formed directly on the inner conduc(cid:173)
`tive layer by means of an electroless plating method. The so
`ferrite film may essentially consist of an oxide metal compo(cid:173)
`sition, the metal composition being represented by the for(cid:173)
`mula of FeaNi6ZncCod, where: a+b+c+d=3.0; 2.l~a~2.7;
`0.l~b~0.3; 0.l~c~0.7; and 0~d~0.15.
`An appreciation of the objectives of the present invention
`and a more complete understanding of its structure may be
`had by studying the following description of the preferred
`embodiment and by referring to the accompanying drawings.
`
`55
`
`2
`FIG. 3A is a view schematically showing a film formation
`apparatus that is used for forming a ferrite film according to
`an embodiment of the present invention;
`FIG. 3B is a top view schematically showing an arrange(cid:173)
`s ment of targets onto a turn table of the film formation appa(cid:173)
`ratus of FIG. 3A;
`FIG. 4 is a view schematically showing an evaluation sys(cid:173)
`tem for evaluating noise suppression result, which is used in
`an embodiment of the present invention;
`FIG. 5 is a cross-sectional view schematically showing a
`four-layer printed circuit board (a) according to an embodi(cid:173)
`ment of the present invention;
`FIG. 6 is a cross-sectional view schematically showing a
`four-layer printed circuit board (b) according to another
`15 embodiment of the present invention;
`FIG. 7 is a cross-sectional view schematically showing a
`four-layer printed circuit board ( c) according to still another
`embodiment of the present invention;
`FIG. 8 is a graph showing a radiation noise spectrum of a
`four-layer printed circuit board (a') in accordance with a
`comparative example;
`FIG. 9 is a graph showing a radiation noise spectrum of the
`four-layer printed circuit board (a) of FIG. 5;
`FIG. 10 is a graph showing a radiation noise spectrum of a
`four-layer printed circuit board (b') in accordance with
`25 another comparative example;
`FIG. 11 is a graph showing a radiation noise spectrum of
`the four-layer printed circuit board (b) of FIG. 6;
`FIG. 12 is a graph showing a radiation noise spectrum of a
`four-layer printed circuit board ( c') in accordance with a still
`30 another comparative example; and
`FIG. 13 is a graph showing a radiation noise spectrum of
`the four-layer printed circuit board (c) of FIG. 7.
`While the invention is susceptible to various modifications
`and alternative forms, specific embodiments thereof are
`35 shown by way of example in the drawings and will herein be
`described in detail. It should be understood, however, that the
`drawings and detailed description thereto are not intended to
`limit the invention to the particular form disclosed, but on the
`contrary, the intention is to cover all modifications, equiva-
`40 lents and alternatives falling within the spirit and scope of the
`present invention as defined by the appended claims.
`
`DESCRIPTION OF PREFERRED
`EMBODIMENTS
`
`The present inventor have studied the problem of JP-A
`2006-100608 or JP-A 2006-019590 and have found out the
`cause of the problem. First explanation will be made about the
`cause of the problem.
`In general, when a noise suppression member or material is
`disposed directly on a transmission line such as a signal
`pattern formed on a printed circuit board, its noise suppres(cid:173)
`sion effect is represented by the following formula (1):
`
`Ptoss ex: M. µ" . f. c5,
`Pin
`
`(1)
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a view schematically showing a magnetic inter(cid:173)
`action in a ferrite film according to an embodiment of the
`present invention;
`FIG. 2 is a view schematically showing imaginary perme(cid:173)
`ability (µ") properties of an existing noise suppression sheet
`made of complex magnetic material and a ferrite film accord(cid:173)
`ing to an embodiment of the present invention;
`
`where P1osJP,n shows noise suppression effect per unit line
`length, M is coupling coefficient between the noise suppres-
`60 sion member and high-frequency magnetic flux caused by a
`current flowing the transmission line, and Ii is a thickness of
`the noise suppression member.
`Coupling coefficient M is influenced by a clearance
`between the noise suppression member and the transmission
`65 line; a large clearance may remarkably deteriorate the cou(cid:173)
`pling coefficient M. Therefore, removal of the clearance is
`required to obtain a large noise suppression effect. However,
`
`Ex.1014
`APPLE INC. / Page 11 of 16
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`

`US 8,164,001 B2
`
`4
`layer printed circuit board. Since the large distance between
`the conductive layers increases noise radiation, the large
`thickness Ii of the noise suppression member cannot be
`adopted in practical use.
`In order to solve the problem of the JP-A 2006-100608 or
`JP-A 2006-019590, it is desirable that a noise suppression
`member or material has a large coupling coefficient M and a
`large product (µ,xQ but has a small thickness Ii. In general, it
`is impossible to obtain a large product (µ,xfr) over the con-
`IO straint of the Snoek's law. However, if the shape of the noise
`suppression member is considered as an additional coeffi(cid:173)
`cient, a demagnetizing field Niz)xMs along its thickness
`direction serves to heighten the precession energy of the spin.
`15 By using the demagnetizing field Ni z )xMs, the formula (3) is
`rewritten into the following formula (6):
`
`y
`f,(for film) = 'b; ·
`
`(6)
`
`3
`if a composite magnetic sheet is used as a noise suppression
`member, an adhesive tape is used to fix the composite mag(cid:173)
`netic sheet to the transmission line; it is difficult to omit the
`adhesive tape in practical use. The thickness of the adhesive
`tape deteriorates the coupling coefficient M of the composite 5
`magnetic sheet. In addition, the general complex magnetic
`material as disclosed in P-A 2006-100608 or JP-A 2006-
`019590 comprises magnetic particles and a polymer binding
`them. The polymer also provides substantial gaps between
`the transmission line and the magnetic particles. The substan(cid:173)
`tial gaps also cause the deterioration of the coupling coeffi(cid:173)
`cient M of the composite magnetic sheet.
`With reference to the formula (1), a property of a noise
`suppression member also depends upon a magnitude of
`imaginary part permeabilityµ" of the noise suppression mem(cid:173)
`ber and its frequency characteristic or its distribution profile.
`Especially, the following three conditions are very important:
`1) a product (µ,xQ of initial permeability µ, and a resonance
`frequency fr is large; 2) the resonance frequency fr is control(cid:173)
`lable in a wide frequency range; and 3) the distribution profile 20
`changes abruptly towards its peak. The product (µ,xfr) is
`influenced by saturation magnetization Ms and an anisotropic
`magnetic field Ha unique to a used material as well as the
`shapes of the material. The initial permeability µ, and the
`resonance frequency fr are represented by the following for(cid:173)
`mulas (2) and (3), respectively, and the initial permeabilityµ, 25
`and the resonance frequency fr meet the following formula
`(4):
`
`Note here that anisotropic magnetic field Ha, saturation
`magnetization Ms and permeability ~ of vacuum meet the
`following condition: HaxM)µ 0>> 1. In consideration of the
`condition, a magnetic film has a larger demagnetizing field
`Niz)xMs in comparison with that of a magnetic bulk that has
`the chemical composition same as the magnetic film. There(cid:173)
`fore, the magnetic film has a resonance frequency fr higher
`than the magnetic bulk. For example, the ferrite-plated film
`has a product (µ,xfr) larger by an order of magnitude than that
`of a sintered ferrite bulk or a thick film magnetic material. In
`addition, the magnetic film essentially consisting of magnetic
`material, ex. the above-mentioned ferrite-plated film, has a
`large coupling coefficient M in comparison with a complex
`magnetic material, because of no polymer and no adhesive
`sheet. In consideration of the demagnetizing field Njx)xMs
`of the composite magnetic sheet, the magnetic film essen(cid:173)
`tially consisting of magnetic material has a product (µ,xfr)
`40 larger than that of the composite magnetic sheet. Further(cid:173)
`more, the magnetic film has a thickness Ii smaller than manu(cid:173)
`facturing tolerances of the printed circuit board; the small
`thickness Ii does not influence the size of the printed circuit
`board.
`Based on the above discussion, a multilayer printed circuit
`board according to an embodiment of the present invention
`includes an inner magnetic layer, which essentially consists
`of magnetic material and is formed by an action of chemical
`bond or van der Waals force without using any non-magnetic
`binder such as a polymer. Specifically, the ferrite-plated film
`is used as the inner magnetic layer in the present embodiment.
`The ferrite-plated film is formed by a ferrite plating method.
`Preferably, the ferrite-plated film is formed by an electroless
`plating method.
`For example, the ferrite plating method is a method as
`disclosed in U.S. Pat. No. 4,477,319, the contents of which
`are incorporated herein by reference in their entireties. The
`ferrite plating method of the present embodiment comprises
`the steps of: preparing a specific solution containing at least
`60 ferrous ions; bringing a surface of a target into the specific
`+ ions, or Fe2
`solution to cause Fe2
`+ ions and other metal
`hydroxide ions, to be absorbed on the surface of the target;
`oxidizing the absorbed Fe2 + ions to obtain Fe3 + ions to cause
`the Fe3
`+ ions and metal hydroxide ions in the specific solution
`65 to undergo a ferrite crystallization reaction so that a ferrite
`film is formed on the surface of the target. The target of the
`ferrite plating according to the present embodiment is, for
`
`y
`f,(for bulk) = 'b; Ha
`
`yM,
`!,·µ; = -3-,
`nµo
`
`(2) 30
`
`(3)
`
`(4) 35
`
`where µ0 is permeability of vacuum.
`As understood from the formula (4), the product (µ,xQ is
`proportional to saturation magnetization Ms. In other words,
`the product (µ,xfr) is basically constant if the materials have
`the same saturation magnetization Ms; this is the Snoek' slaw.
`Furthermore, a noise suppression member of a complex
`magnetic material or a pre-impregnation sheet including the
`noise suppression member is also influenced by another
`demagnetizing field NiX)xMs along a magnetic path. The
`demagnetizing field Njx)xMs depends upon the shapes of
`the magnetic particles. It is assumed that the above-men(cid:173)
`tioned demagnetizing field Nix)xMs is caused by keeping
`the magnetic particles away from each other by the nonmag(cid:173)
`netic polymer. The demagnetizing field Nix)xMs influences
`on effective permeability µe of a magnetic material in an open
`magnetic path, as represented by the following formula (5).
`Thus, the noise suppression member of the complex magnetic
`material or the pre-impregnation sheet has extremely small
`effective permeability µe along the magnetic path.
`
`1
`µ, * Nd(x)
`
`(SJ
`
`As understood form the formula (1 ), a noise suppression
`effect of a noise suppression member further depends upon
`the large thickness Ii of the noise suppression member. How(cid:173)
`ever, the large thickness Ii of the noise suppression member
`makes a large distance between conductive layers in a multi-
`
`45
`
`50
`
`55
`
`Ex.1014
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`

`US 8,164,001 B2
`
`5
`example, an inner conductor layer included in the multilayer
`printed circuit board of the present embodiment.
`As shown in FIG. 1, the ferrite-plated film comprises a
`plurality of colunmar crystals, which have high homogeneity.
`In the ferrite-plated film, neighboring ones of the columnar
`crystals are magnetically coupled with each other by a strong
`exchange interaction. Therefore, the ferrite-plated film has
`small variation of anisotropic magnetic fields. The small
`variation of anisotropic magnetic fields causes its distribution
`profile of frequency property to change abruptly towards its
`peak so that the ferrite-plated film can provide a suitable noise
`suppression effect without reducing a signal frequency. In
`addition, because the above-mentioned exchange interaction
`makes an extremely small demagnetizing field Nix)xMs
`along a magnetic path, the effective permeability µe of the
`ferrite film is substantially equal to the permeability unique to
`the material. The permeability distribution property of the
`ferrite film is based on the ferromagnetic resonance thereof
`and is therefore superior to that of a composite magnetic
`sheet, as shown in FIG. 2. Furthermore, since the ferrite- 20
`plated film can be formed directly on an inner conductive
`layer of the multilayer printed circuit and the ferrite-plated
`film includes no polymer, there is no clearance or gap
`between the ferrite-plated film and the inner conductive layer.
`Therefore, the coupling coefficient M of the ferrite film is 25
`very close to its theoretical maximum value (Mmax=l). Thus,
`the ferrite film has the large coupling coefficient M and the
`large product (µ,xQ within the noise frequency range but has
`the small thickness Ii. Therefore, the ferrite film has a superior
`noise suppression effect when used within a multilayer 30
`printed circuit board.
`With reference to IEC62333-2 defined in the IEC (Interna(cid:173)
`tional Electrotechnical Commission) as a property evaluation
`standard of a noise suppression sheet, a micro-strip line
`(MSL) board was prepared by fabricating a double-sided 35
`printed circuit board, and conduction noise suppression effect
`of the ferrite-plated film was evaluated.
`Ferrite films for evaluation were formed by using a film
`formation apparatus as schematically shown in FIGS. 3A and
`3B. The illustrated film formation apparatus comprises 40
`nozzles 101,102, permanent magnets 103, tanks 105,106 and
`a turn table 107. The tanks 105, 106 contain the solutions for
`ferrite plating and other solutions for oxidization; the solu(cid:173)
`tions for ferrite plating have the respective compositions as
`shown in the above table.
`In order to form ferrite films by the use of the illustrated
`apparatus, targets 104 were put onto the turn table 107 so that
`each target 104 was positioned between two permanent mag(cid:173)
`nets 103, as shown in FIG. 3B. The permanent magnets 103
`
`6
`were used to apply onto the surface of the target 104 a mag(cid:173)
`netic field parallel to the surface to control magnetic anisot(cid:173)
`ropy in the ferrite-plated film. The desirable magnitude of the
`applied magnetic field in this embodiment is 0-50 Oe; the
`5 magnitude may be determined in response to the desirable
`magnitude of the magnetic anisotropy. The solutions were
`provided from the tanks 105, 106 onto the targets 104 through
`the nozzles 101, 102. Upon the provision of the solutions, first
`and second steps were repeatedly performed in turn so as to
`10 form the ferrite films on the targets 104, wherein the first step
`is of providing the solution onto one of the targets 104 through
`the nozzle 101, followed by removing excess liquid of the
`solution by using a centrifugal force of the turn table 107;
`15 likewise, the second step is of providing the solution onto the
`targets 104 through the nozzle 102, followed by removing
`excess liquid of the solution by using a centrifugal force of the
`turn table 107.
`More in detail, MSL boards or polyimide sheets were
`prepared as the targets 104 and were mounted on the turn
`table 107. Each MSL board comprised a glass epoxy board
`that had a thickness of 1.6 mm and a shape of 80 mm square.
`One surface of the glass epoxy board was formed with a strip
`conductor, while the other surface of the glass epoxy board
`was formed with a ground conductor of a uniform pattern.
`The strip conductor was positioned on the center line of the
`surface of the glass epoxy board and had a width of about 3
`mm and a length 80 mm. The MSL's characteristic imped(cid:173)
`ance was 50 Q. The MSL board was mounted on the turn table
`107 so that the ground conductor was in contact with the turn
`table 107. On the other hand, each polyimide sheet had a
`thickness of 25 µm and a shape of 8 cm square.
`Next, the turn table 107 was turned at 150 rpm while
`deoxidized ion-exchange water was provided on the MSL
`board or the polyimide sheet under a heat condition up to 90°
`C. Next, nitrogen gas was introduced into the film formation
`apparatus so that deoxide atmosphere was created in the
`apparatus. Each solution for ferrite plating (reaction solution)
`was formed by dissolving FeCl2 -4H2 O, NiCl 2 -6H2 O, ZnCl2 ,
`CoC12 -6H2O into deoxidized ion-exchange water for each
`film shown in the following table 1. On the other hand, an
`oxidizing solution is formed by dissolving NaNO2 and
`CH3COONH4 into deoxidized ion-exchange water. The reac-
`45 tion solution and the oxidizing solution were provided onto
`the targets 104 through the nozzles 101, 102, wherein each of
`their flow rates is about 40 ml/min. As a result of the above
`processes, black ferrite films were formed on the surfaces of
`the targets 104, respectively.
`
`TABLE 1
`
`Film
`Composition
`(mo!%)
`
`L
`
`µa' at
`
`µb' at
`
`µa'/µb'
`at
`
`tx µ" at
`µ" at
`5 GHz 5GHzX
`
`fr
`
`ID
`
`#1
`#2
`
`#3
`#4
`#5
`#6
`
`#7
`#8
`#9
`#10
`
`Example
`Comparative
`Example
`Example
`Example
`Example
`Comparative
`Example
`Example
`Example
`Example
`Example
`
`Target
`
`Fe Ni Zn Co
`
`(mm)
`
`(µm)
`
`Lit
`
`50MHz 50MHz 50MHz
`
`2.5 0.2 0.3 0.00
`MSL
`Polyimide 2.5 0.2 0.3 0.00
`Sheet
`MSL
`MSL
`MSL
`MSL
`
`2.5 0.2 0.3 0.00
`2.4 0.3 0.3 0.00
`2.5 0.2 0.3 0.00
`2.5 0.2 0.3 0.00
`
`MSL
`MSL
`MSL
`MSL
`
`2.2 0.1 0.7 0.00
`2.5 0.2 0.3 0.01
`2.1 0.2 0.6 0.15
`2.1 0.2 0.6 0.14
`
`80
`80
`
`80
`80
`80
`80
`
`80
`80
`80
`80
`
`3.0
`3.0
`
`4.0
`2.2
`0.8
`0.5
`
`2.3
`3.0
`3.0
`3.1
`
`26667
`26667
`
`20000
`36364
`100000
`160000
`
`34783
`26667
`26667
`25806
`
`40
`45
`
`38
`38
`34
`41
`
`120
`40
`32
`15
`
`40
`45
`
`38
`38
`34
`41
`
`120
`34
`16
`30
`
`0.8
`2.0
`0.5
`
`X
`
`15
`13
`
`14
`15
`13
`15
`
`8
`15
`10
`10
`
`(µm)
`
`(MHz)
`
`45
`39
`
`56
`33
`10
`8
`
`18
`45
`30
`31
`
`400
`300
`
`390
`410
`410
`410
`
`100
`400
`400
`400
`
`Ex.1014
`APPLE INC. / Page 13 of 16
`
`

`

`7
`
`US 8,164,001 B2
`
`TABLE I-continued
`
`8
`
`Comparative
`Example
`Comparative
`Example
`Comparative
`Example
`Example
`Comparative
`Example
`
`#11
`
`#12
`
`#13
`
`#14
`#15
`
`MSL
`
`2.3 0.2
`
`0.4 0.07
`
`MSL
`
`2.3 0.2
`
`0.4 0.06
`
`MSL
`
`2.3 0.2
`
`0.3 0.20
`
`MSL
`MSL
`
`2.7 0.2
`2.8 0.1
`
`0.1 0.00
`0.1 0.00
`
`80
`
`80
`
`80
`
`80
`80
`
`2.9
`
`27586
`
`35
`
`3.0
`
`26667
`
`2.0
`
`40000
`
`3.0
`3.0
`
`26667
`26667
`
`5
`
`5
`
`35
`34
`
`5
`
`36
`
`5
`
`35
`34
`
`7.0
`
`0.1
`
`11
`
`11
`
`4
`
`12
`11
`
`32
`
`33
`
`8
`
`36
`33
`
`400
`
`410
`
`2500
`
`430
`440
`
`MSL Transmission Characteristic
`(Line Parallel to Direction for µa')
`
`MSL Transmission Characteristic
`(Line Parallel to Direction for µb')
`
`ID
`
`Ploss/Pin LI.Ploss/Pin
`Ploss/Pin
`Sll at 50 LI.Ploss/Pin LI.Ploss/Pin LI.Ploss/Pin Sl 1 at 50
`MHz (dB) at 50 MHz at 1 GHz
`at 5 MHz MHz (dB) at 50 MHz at 1 GHz
`at 5 GHz
`
`8.E+03
`8.E+03
`
`-30
`-32
`
`-30
`-32
`
`0
`0
`
`0
`0
`
`0
`
`Example
`Comparative
`Example
`Example
`Example
`Example
`Comparative
`Example
`Example
`Example
`Example
`Example
`Comparative
`Example
`Comparative
`Example
`Comparative
`Example
`Example
`Comparative
`Example
`
`#1
`#2
`
`#3
`#4
`#5
`#6
`
`#7
`#8
`#9
`#10
`#11
`
`2.E+02
`9.E+03
`9.E+03
`9.E+03
`
`2.E+05
`8.E+03
`8.E+05
`1.E+06
`2.E+04
`
`-20
`-35
`-40
`-42
`
`-36
`-31
`-36
`-44
`-38
`
`#12
`
`2.E+04
`
`-42
`
`#13
`
`3.E+04
`
`-42
`
`#14
`#15
`
`1.E-01
`7.E-02
`
`-28
`-18
`
`0
`0
`
`0
`0
`0
`0
`
`0
`0
`0
`0
`0
`
`0
`
`0
`
`0
`0
`
`0
`0
`
`0
`0
`0
`0
`
`0
`0
`0
`0
`0
`
`0
`
`0
`
`0
`0
`
`0
`
`0
`0
`
`0
`
`0
`
`0
`
`-20
`-35
`-40
`-42
`
`-35
`-30
`-43
`-36
`-42
`
`-38
`
`-42
`
`-28
`-18
`
`0
`0
`0
`0
`
`0
`0
`0
`0
`0
`
`0
`
`0
`
`0
`0
`
`0
`0
`0
`0
`
`0
`0
`0
`0
`0
`
`0
`
`0
`
`0
`0
`
`0
`0
`
`0
`
`0
`
`0
`
`X· ... µ" was measured along a direction parallel to a greater one ofµa' and µb'
`
`where rand Tare reflection coefficient and transparent coef(cid:173)
`ficient, respectively, and are defined by the following formu(cid:173)
`las (9) and (10), respectively.
`
`S21~20 loglTI
`
`(9)
`
`(10)
`
`35
`
`Analyses were carried out on the thus obtained ferrite
`films. Their permeability-frequency characteristics were
`measured by using a permeameter (i.e. permeability mea(cid:173)
`surer) based on the shielded deep coil method. Their trans(cid:173)
`mission loss li.P1os/P,n were measured as their noise suppres- 40
`sion effects by using an evaluation system illustrated in FIG.
`4. In FIG. 4, a reference numeral 202 indicates anMSL board
`or a polyimide sheet, and another reference numeral 204
`indicates the ferrite film formed thereon. As shown in FIG. 4,
`both ends of the MSL board 202 were connected to a network 45
`analyzer 203 by using coaxial cables 201. In a case of the
`polyimide sheet, the measurement was carried out while the
`polyimide sheet was disposed on a simple MSL board with no
`ferrite film, and uniform weighting was applied on the sheet
`by using a weight of 500 g. Their results were standardized
`with respect to a simple MSL board formed with no ferrite
`film. The standardized results and other measured properties
`are shown in the above table 1, wherein µ'a is real part per(cid:173)
`meability of each ferrite film along a direction "a" parallel to
`its surface, µ'b is real part permeability of the ferrite film
`along another direction "b" parallel to the surface of the film
`but perpendicular to the direction "a".
`The transmission loss li.P1os/P,n of each ferrite film was
`calculated on the basis of the following formulas (7) and (8):
`
`In the table 1, "t" is a thickness of each ferrite film, and "L"
`is a minimum length of each ferrite film. As apparent from the
`table 1, each ferrite film except for the ferrite films #6 and #13
`has a product (µ"xt) equal to or greater than 10 µm. In addi(cid:173)
`tion, each ferrite film meets the conditions oft~50 µm and
`L/t~l000. In other words, every ferrite film is so sufficiently
`50 thin that its demagnetizing field Njx)xM5 is very small.
`Furthermore, each of the ferrite films except for the ferrite
`film #15 has a sufficiently small reflection property (S 11 ) due
`to its resistivity PDc not smaller than 0.1 Qm, irrespective of
`its large area size. In particular, each of the ferrite films except
`55 for the ferrite films #11 and #12 meets the condition of
`0.5~x~2.0, where x is µ'a/µ'b, because each film has very
`small magnetic anisotropy or no magnetic anisotropy in its
`plane. In addition, each of the ferrite films #1, #3, #4, #5, #7,
`#8, #9, #10 and #14 essentially consists of an oxide metal
`60 composition, the metal composition being represented by the
`a+b+c+d=3.0;
`of FeaNi6ZncCod, where:
`formula
`2.l~a~2.7; 0.l~b~0.3; 0.l~c~0.7; and 0~d~0.15. As
`the result, each of the ferrite films #1, #3, #4, #5, #7, #8, #9,
`#10 and #14 has an appropriate transmission loss property
`li.P1os/P,n that is low within a relatively lower frequency band
`of about 50 MHz, i.e. a frequency band for transmitted sig(cid:173)
`nals, but is high within a relatively higher frequency band of
`
`65
`
`Ptoss
`P;n(MSL+Ferrite) - P;n(MSL)'
`
`(7)
`
`(8)
`
`Ex.1014
`APPLE INC. / Page 14 of 16
`
`

`

`US 8,164,001 B2
`
`9
`several GHz, i.e. a frequency band for conduction noise, in
`comparison with the other ferrite films #2, #6, #11, #12, #13,
`and #15.
`For further analysis directed to influence of each film's
`aspect ratio Lit to its permeability, ferrite films were formed 5
`on micro-strip line boards in a manner same as the above(cid:173)
`explained manner, the micro-strip line boards were cut to
`obtain the shape of 4 mm square, and the permeability of each
`obtained 4 mm square was measured by using the shielded
`loop coil method. The analysis result is