© TOKIN 20191/23
Soft magnetic Metal-flake Composite Material
Suitable for High Frequency Power Modules
19 Mar. 2019
Ken’ichi Chata’ni
TOKIN Corporation
© TOKIN 20192/23
Ken’ichi Chata’ni, Ph.D.(Physics)
Manager, Advanced Materials R&D DivisionTOKIN Corporation
7-1 Koriyama 6-Chome, Taihaku-ku, Sendai, Miyagi 982-8510 Japan
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TOKIN History
1930 19801930
Name changed to TOKIN Corporationbecome a 100% subsidiary of the United States based KEMET Corporation
1990 2000 2010
April 1938 as University Startups
Established to commercialize KS magnetic steel (by Prof.
Kotaro Honda) and Sendust (by Prof. Masumoto Hakaru), both
invented at Tohoku Imperial University, Sendai, Japan.
October 1988
April 2002
February 2013
Became NEC TOKIN Corporation(3 SBUs from NEC: capacitors, relays, and batteries)
Name changed to
TOKIN Corporation
Started business and capital partnership
with KEMET Corporation
April 2017
Main ProductsTantalum capacitors,
Electric double-layer capacitors,
EMI/Noise suppression components,
Power inductors, Transformers,
Piezoelectric devices, Sensors.S
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Material characteristics of FlakeCompositeTM ,
in comparison with existing magnetic materials.
-Permeability, magnetic saturation, core loss, etc.
Inductor performance benchmarking.
PCB embedded inductor test fabrication result.
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Demands: Shorten the distance from DC/DC converter to load.
Higher DC current / Higher switching frequency
Motivation
Back surface mount
Processer
Inductor Inductor
Inductor
Processer
PCB embedding
Processer
3D mount
Processer
Conventional
Spread of GaN
Integratable L, C
Low-profiled inductor for integrated DC/DC converter is required.
PCB embed enabling magnetic material will also be required in future.
Inductor
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FlakeCompositeConventional Metal composite
Permeability >300(Same as ferrites)
< 40
Metal-flake
Compacting
Technology
Thickness >0.5mmBrittle
>50μmFlexible
Heat durability <200℃Organic binder
>200℃Inorganic binder
Enable PCB Embedding
Favorable for power modules
Smaller component's volume
What is FlakeCompositeTM?
t=50μm
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0.0
0.5
1.0
1.5
2.0
100 100010
Bs(T
)
MnZnNiZn
CoZrO(film)
CoZrTa(film)
CoNiFe(film)
Fe nanocrystal
Permalloy
FeSiAl(Sendust)
FeSi
Fe amorphous
Permeability (1MHz)
PCB embeddedMagnetic Material
Conventional metal composite Low permeability
Ferrites
Deposited Film
Brittle
Difficult to increase
the core volume.
High permeability (300 at 1 MHz.)
50m to 2mm thickness
Thin, Flexible(Rigid)
FlakeComposite
Comparison of Magnetic Materials for PCB Embedding
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Powder Shape Permeability Min. bend radius(Arb. unit)
35 10
160 4
300 1
30m
Effect of Powder Shape on Permeability and Flexibility
10 times improvement in
permeability and flexibility
t=50μm
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0
100
200
300
400
0.1 1 10 100
Perm
eab
ility
(Re, I
m)
Frequency(MHz)
NiZn ferrite
FlakeComposite
μ’// = 300
μ≦ 5
Comparable to NiZn ferrite for MHz
power application.
Frequency dispersion of complex permeability
Limitation
Lower Out-plane permeability.
Perm
eabili
ty (
Re,
Im)
Frequency (MHz)
Permeability vs Frequency
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0
500
1000
1500
-50 -25 0 25 50 75 100 125 150 175
Pcv(m
W/cc, 1M
Hz
Bm
25m
T)
Temp (℃)
0
1000
2000
0 1 2 3 4 5
Pcv(m
W/cc)
f(MHz)
f×Bm=25MHz・mT
23℃
Core loss of FlakeComposite is comparable to NiZn ferrite,
but much larger than MnZn ferrite at few MHz.
NiZn ferrite
MnZn ferrite
Conventional
Metal Composite
Core Loss vs Temp.
FlakeComposite
FlakeComposite
Core Loss
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0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 2000 4000 6000 8000
B (
T)
H (A/m)
Soft-saturation in FlakeComposite.
Smaller drop of saturated magnetic moment against temperature,
comparing to MnZn ferrite.
125℃
25℃
MnZn ferrite
FlakeComposite
Conventional
Metal Composite
Magnetic Saturation (BH curve)
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0
10
20
30
40
50
60
70
80
0 2000 4000 6000 8000
Perm
eab
ility
Hdc(A/m)
125℃
25℃
MnZn ferrite
FlakeComposite
Conventional
Metal Composite
In metals, permeability under DC-bias field is insensitive to temperature.
In metals, permeability survives under high DC-bias field.
In MnZn ferrite and FlakeComposite, effective
permeability under zero bias field is tuned to be 70 by
corresponding demagnetizing coefficient, i.e, air-gap.
N=0.01384
N=0.01091
N=0
Permeability under DC-bias Field
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0
50
100
150
200
250
300
0.1 1 10 100
Pe
rme
ab
ilit
y(R
e,
Im)
Frequency(MHz)
0
10
20
30
40
50
60
70
80
90
100
0 500 1000
Perm
eab
ilit
y C
han
ge(%
)
Plane Pressure(kgf/cm2)
Only 7.6% permeability decrease
under 1000kgf/cm2 compression.
Plane Pressure(kgf/cm2)
-7.6%
FlakeComposite
Apply 1000kgf/cm2 plane pressure
on the toroidal core.
After 1000kgf/cm2
compression
Initial
Only 2.7% permeability decrease
after 1000kgf/cm2 compression.
No apparent damage was found.
Effect of Plane Compression
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Material characteristics of FlakeCompositeTM ,
in comparison with existing magnetic materials.
-Permeability, magnetic saturation, core loss, etc.
Inductor performance benchmarking.
PCB embedded inductor test fabrication result.
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Lateral flux
h
Vertical flux
1turn
2turn3turn
Lateral Flux Inductor Structure
Qiang Li, Fred C. Lee, “High Inductance Density Low-Profile Inductor Structure for Integrated Point-of-Load Converter”, 2009
IEEE Applied Power Electronics Conference and Exposition (APEC), Washington, District of Columbia, Feb. 15 – 19, 2009, pp.
1011 – 1017.
Dongbin Hou, Yipeng Su, Qiang Li, Fred C. Lee, “Improving the Efficiency and Dynamics of 3D Integrated
POL”, IEEE Applied Power Electronics Conference and Exposition (APEC), 2015, pp. 1011 – 1017.
FlakeComposite is suitable to
demonstrate the proposed
advantage of “Lateral flux”
inductor design.
As inductor goes thinner, the
advantage of “Lateral flux”
inductor structure should be
more prominent.
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0
10000
20000
30000
0 1 2 3 4 5 6
L x
Im
ax /
DC
R(n
H・A
/mΩ
)
Inductor Height(mm)Imax≧20A
FlakeComposite
Lateral flux
The advantage of FlakeComposite Lateral flux inductor becomes
prominent as the inductor height goes lower.
Benchmarking Result
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Storage Result (N=22)
-50℃ 1000h Pass
150℃ 1000h Pass
Unbiased Hast
With MSL 3
Pre-Conditioning130℃85% 96h
Pass33.3psia(2.3atm)
JESD22-A119 JESD22-A103 Condition B
Heat Cycle
-65⇔150℃ 500cycle Pass
JESD22-A104 Condition C Soak Mode 4
JESD22-A118
MSL test (Level 1)
Pre-bake 125℃ 24h
PassMoisture Soak 85℃85%RH 192h
Reflow 260℃ x 3
J-STD-020E
Sample Structure
・Tin plated lead frame and Cu pins
(without insulation coating) are attached
on the FlakeComposite core. Image
Hi Temp and Humidity
85℃85% 1000h Pass
MIL-STD-202 Method 103
• Acceptance Criteria:
・ Change of Ls, Rs and
DCR<10% pre-test to post-test.
・ No cracks, chips or
discoloration
AEC-Q200 compatible. (RoHS2.0, Halogen free, REACH compliant.)
13mm
Reliability Test Example (On samples to CPES)
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Material characteristics of FlakeCompositeTM ,
in comparison with existing magnetic materials.
-Permeability, magnetic saturation, core loss, etc.
Inductor performance benchmarking.
PCB embedded inductor test fabrication result.
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Y. Su, W. Zhang, Q. Li, F. C. Lee, and M. Mu, "High frequency integrated Point of Load
(POL) module with PCB embedded inductor substrate," in Energy Conversion Congress
and Exposition (ECCE), 2013 IEEE, 2013, pp. 1243-1250.
Similar prototypes were fabricated.
PCB Embedded Inductor Demonstrated by CPES
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2 turn
DCR
2.8mΩ
3 turn
DCR
4.4mΩ
With inserted
pins
0.8mΩ
With inserted
pins
2.1mΩ
0
50
100
150
200
250
300
350
0 10 20 30 40
L(n
H)
@1M
Hz
Idc(A)
2 turn
3 turn
Upside Downside
Upside Downside
t2.5mm
12mm
Embedded core size
9 x 8 x t1.5mm
PCB Embedded Inductor Prototype
Cu t=0.2
CuΦ
=0.8
Flake
CompositeFlake
Composite
t=2.7mmFR4
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0
10
20
30
235 255 275 295 315
Co
unt
L(nH, 1MHz)
0
10
20
30
105 115 125 135 145
Co
unt
L(nH, 1MHz)
0
25
50
75
100
125
150
1 10 100 1000
L(n
H)
Frequency(MHz)
1
10
100
1000
1 10 100 1000
|Z|(Ω
)
Frequency(MHz)
0
100
200
300
1 10 100 1000
L(n
H)
Frequency(MHz)
1
10
100
1000
1 10 100 1000
|Z|(Ω
)
Frequency(MHz)
2 turn (n=100)
3 turn (n=100)
-10%
±3σ
±3σ
+10%Ave.
125nH
Ave.
277nH-10% +10%
SRF=400MHz
SRF=250MHz
Tight tolerance of inductance is readily achieved in prototypes.
Dispersion of Inductance , |Z|
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PCB embedded inductor to minimize:
- PCB board area.
- parasitic inductance of Cu trace.
Power Inductors
Ferrite FlakeCompositeTM
40% height reduction with
FlakeComposite inductor.
Embedded noise shielding layer
Flexible shielding layer (for WPT)
- Combined with PCB embedding technology.
FlexSuppressor® Flex "Embedded"
Suppressor
Magnetic Sheets
Application Target
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FlakeCompositeTM is:
-Thin, Flexible, PCB-embed-enabling,
-High permeability at multi-MHz swithcing frequency,
-High-saturated magnetic moment than ferrite,
-High temperature tolerant
soft magnetic material for power supply application.
We believe this material will contribute to the miniturization of
electronic circuits, especially in:
- DC/DC converters,
- Wireless Power Transfer system.
We are continuing to scale-up this technology for use in several applications.
Summary
Thank you very much for your attention.