the third international workshop on power supply on...
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Spin Device Technology Center, Shinshu University, Nagano, Japan
The Third International Workshop on Power Supply on Chip 2012
Magnetic core power inductor embedded in glass/epoxy interposer
toward power supply integrated in LSI Package Toshiro Sato*, Makoto Sonehara, Hiroki Kobayashi, Fumihiro Sato, Kazuhiro Hagita Spin Device Technology Center, Shinshu University, Nagano, Japan
Rie Takeda, Nobuhiro Matsushita Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Japan
Tomohiro Fujii, Shinji Nakazawa, Hiroshi Shimizu, Kazutaka Kobayashi SHINKO ELECTRIC INDUSTORIES Co. Ltd., Nagano, Japan
Yasuhiro Shinozuka, Hiroshi Fuketa, Koichi Ishida, Makoto Takamiya, Takayasu Sakurai Institute of Industrial Science, the University of Tokyo
PowerSoc2012
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□ Outline Power delivery to LSIs ・ From board-level to package-level (chip-level) power grid Need for integrated power supply technology ・ Power magnetics on chip or embedded in package ?
Objective of this work ・ Final goal : Package-level DC power grid with integrated power supplies in LSI package
This study ・ A possibility of embedded power inductor for power supply integrated in LSI package, performance ?, cost ?, ・・・ Fabrication and evaluation of embedded magnetic core power inductor
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The Third International Workshop on Power Supply on Chip 2012
PowerSoc2012
Spin Device Technology Center, Shinshu University, Nagano, Japan
□ Technology trend of power delivery to LSIs
10 cm
1 cm
1mm
100 µm
10 µm
DC-DC
DC-DC in a package
C L Switches and control circuit LSI
LSI DC-DC
Conventional
Current stage (Board-level power grid)
DC
pow
er li
ne le
ngth
LSI Switches and control circuit L C
POL DC power supply (Pont of load)
Power magnetics in package
Power magnetics on chip
DC-DC in a chip
LSI
Next stage (Package-level power grid)
Final stage ? (Chip-level power grid)
Conventional Current stage Next stage Final stage
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Air-core inductor ; Merit and demerit
■ Low cost (only winding) ■ Low inductance, large foot-print ■ Local EMI noise (leakage magnetic flux)
P. Hazucha et al., 2004 Symp. VLSI Circuits, 256,(2004) K. Ishida et al. : ISSCC2009, 13.2, (2009) INTEL(233MHz DC-DC converter, 90 nm-CMOS)
Driv
er
Output80nH
PWM controller
Spiral inductor
Si CMOS LSI
Silicon interposer
(Flip chip)Si CMOS LSI
Silicon interposer
(Flip chip)
Si CMOS LSI
Interposer MIM capacitor
CMOS circuit
Univ. of Tokyo(Air-core spiral on Si-interposer)
CLKREG
MD<1:0>
Synchronizer
Φ 0L<1:0>Φ 1L<1:0>
Φ 2L<1:0>Φ 3L<1:0>
VREFL
VREFHIref
Iload
6.8 nH
SYN
C<1
:0>
SYN
C<1
:0>
SYN
C<1
:0>
SYN
C<1
:0>
V REF
H
V REF
H
V REF
H
V REF
H
V REF
L
V REF
L
V REF
L
V REF
L
V RSH
V RSH
V RSH
V RSH
V RSL
V RSL
V RSL
V RSL
V BR
V BR
V BR
V BR
V SEN
SE
V SEN
SE
V SEN
SE
V SEN
SE
1-phase 1-phase 1-phase 1-phase
R50
VOUT
VPROBE
DC-DC converter chip ; 1280× 990 µm
SMT air-core inductors on package
1.2V → 0.9 V ・0.3 A : 82.5 %, 1.4 V → 1.1 V ・0.4 A : 83.2 %
2.5 nF
Spin Device Technology Center, Shinshu University, Nagano, Japan
Examples of CMOS-switch DC-DC converter using air-core inductor
The Third International Workshop on Power Supply on Chip 2012
PowerSoc2012
□ Possibility of magnetic core power inductor for CMOS-switch DC-DC converter
( )0 032
S
0 0
10 S03
0 1 S1
124R C 1 D1
D L / RD:duty, R C : MOSFET const.
11 L / R1 1
L / R
η =−
+
η =⎛ ⎞
+ −⎜ ⎟η⎝ ⎠
VIN
L C
RS
VOUT
Load
I
W
VIN
Controller
W ; Gate width
850 µm □ 50 µm height 10 nH 60 mΩ > 1 A
Zn-Fe Ferrite inductor fabricated on glass substrate H. Ito et al., INTERMAG 2011 Conf. CV-05, Taipei, May 2011.
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G.Schrom et al., IEEE ICICDT, pp.65-67, Feb. 2006
50
55
60
65
70
75
80
85
90
95
100
1 10 100 1000 10000
Maxim
um co
nver
sion
effic
iency
(%)
Inductor parameter τL= L / RS (nH/ Ω)
180nm-CMOS
65nm-CMOS
45nm- CMOS
Air core spiral on-chip ; t=2um, ≒8nH
Air core spiral on Si interposer ; t=15um, ≒8nH
VIN=1V VOUT=0.5V
Calculated by T. Sakurai et al.
Zn-Fe Ferrite core spiral t=20µm,10nH, 60mΩ
Comparable ! !
The Third International Workshop on Power Supply on Chip 2012
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On-chip inductors
DC-DCConverter
5 mm
4 mm
93 µm
Pad
Cu coilCo-Hf-Ta-Pd
LSI
20 µm
In 2000, Fuji Electric Corp. In 2009, INTEL Corp.
Spin Device Technology Center, Shinshu University, Nagano, Japan
□ Power magnetics on chip or embedded in package? Which will be better solution for power delivery to LSIs?
Power magnetics on chip technology should be established in the future chip-level power grid.
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System in Package (SIP) with DC power grid
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The Third International Workshop on Power Supply on Chip 2012
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By Prof. Sakurai’s Group, The University of Tokyo
Capacitor
Drive
r
Internal Circuit
PWM controller
Si-CMOS LSI (Flip-chip)
Embedded inductor
Capacitor
Drive
r
Internal Circuit
PWM controller
Si-CMOS LSI (Flip-chip)
Interposer
Embedded inductor
Capacitor
Drive
r
Internal Circuit
PWM controller
Si-CMOS LSI (Flip-chip)
Embedded inductor
Capacitor D
rive
r Internal Circuit
PWM controller
Si-CMOS LSI (Flip-chip)
Power-grid controller
Distributed DC power-line
Main DC-DC
Large current L on package
VIN
VOUT
fS
IOUT
VOUT ( 1 - Vout / VIN )
2 fS IOUT
LC =
VIN = 1.5 V, Vout = 1 V, Iout = 1 A, fS = 30 MHz
LC = 5.6 nH
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□ Objective ; Package-level power grid (PLPG) The Third International Workshop on Power Supply on Chip 2012
PowerSoc2012
Power magnetics embedded in package Embedded power inductor in package
Low cost, Low profile ; tens micron height, Small near-EMI ; magnetic core
Glass-epoxy core
Flip-chip CMOS-LSI with DC-DC Flip-chip CMOS-LSI with DC-DC
Build-up layer
C C
Embedded inductor
Magnetic core
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The Third International Workshop on Power Supply on Chip 2012
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□ Objective ; Package-level power grid (PLPG)
Magnetic core fabrication Process-compatible with glass/epoxy interposer
Low temperature process below 200 ℃
◇ Spin-spray method for spinel-ferrite deposition; ≒ 90 ℃ ◇ Screen-printing for Carbonyl Fe/epoxy composite; ≒150℃
FeCl2 + MCl2
PCB Interposer
~90 ℃
Nozzle
Spin-spray method (TIT, Japan)
ペー
基
スクリー Screen mask Paste
Substrate
Post baking (150℃)
Screen-printing method (Shinshu Univ., Japan)
Spin-sprayed ferrite core NaNO2
Composite core Paste ; Carbonyl iron powder and epoxy precursor solution
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□ Magnetic core materials for planar power inductor
The Third International Workshop on Power Supply on Chip 2012
PowerSoc2012
54 vol.% Carbonyl iron powder (CIP)/epoxy composite
5 µm
□ Magnetic core materials for planar power inductor
Zn-Fe ferrite (Zn0.36Fe2.64O4 ) thick film with a columnar-grain structure
Static magnetization curve Permeability vs. frequency
0.57T
1.08T
CIP/epoxy Composite
-400 -200 0 200 400
-1
-0.5
0
0.5
1
Mag
netiza
tion
M
[T]
Applied magnetic field H [A/m]
Zn-Fe ferrite Zn-Fe ferrite
CIP/epoxy composite
µ’
µ’’
10 100 1000 0.1
1
10
100
Frequency f [MHz]
Com
plex
perm
eab
ility
µ’, µ”
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The Third International Workshop on Power Supply on Chip 2012
PowerSoc2012
□ Zn-Fe ferrite planar power inductor on glass In order to confirm an intrinsic potential of the planar inductor
for embedded passives,
・Zn-Fe ferrite inductor has been fabricated on glass substrate. ・Electrical properties have been evaluated.
Glass substrate
20 µm thick, 2-turn copper spiral coil with 50/40 µm line/space and 650 µm □
850 µm
A B
850 µm 10 µm thick Zn-ferrite
Cu
Polyimide
10 µm 6 µm
20 µm 10 µm
50 µm 50 µm
3 µm Cu
40 µm
Glass substrate
A-B cross section
HP4291A f : 1 MHz~1.8 GHz
DUT
100MHz ZL >> Z, ZC << Z DC bias current
0 ~ 2 A
HP4
291A
AC current
DUT ( Z )
ZL
10 nF 90 nH A
B
ZC
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The Third International Workshop on Power Supply on Chip 2012
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Electrical properties
L and Q vs. frequency Superimposed dc current charac.
□ Zn-Fe ferrite planar power inductor on glass
0.5 1 1.5 2
5
10
15
0
Indu
cta
nce L [n
H]
DC current Idc [A] 0
Zn-Fe ferrite core 2-turn spiral
Air core 2-turn spiral
1 10 100 1000 0
10
20
30
Frequency f [MHz]
Indu
cta
nce L [n
H]
Zn-Fe ferrite core 2-turn spiral
Air core 2-turn spiral
Qua
lity f
acto
r Q
0
10
20
30
Rdc = 60 mΩ
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Flux density in Zn-Fe ferrite core @ superimposed dc current 2 A
Spin Device Technology Center, Shinshu University, Nagano, Japan
850 µm 0.57 T
0
0.57 T
0
DC current : 2 A
0.4 T
0.5 1 1.5 2
5
10
15
0
Indu
cta
nce L [
nH
]
DC current Idc [A] 0
Zn-Fe ferrite core
Air core
17% down
Rating dc current over 1 A Possible application to low power POL converter for PLPG
□ Zn-Fe ferrite planar power inductor on glass
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The Third International Workshop on Power Supply on Chip 2012
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Zn-Fe ferrite core 2-turn spiral
Air-core, 3-turn spiral
①Build up layer, ②Glass-epoxy core
(Shinshu Univ., Tokyo Inst. Tech., SHINKO Elec. Ind. Co.)
Cu metal plane
Cu conductor line
60µm 7.5μm thick Zn-ferrite core
Cu metal plane
Cu conductor line
Build up layer (Epoxy/Glass filler)
Zn-Fe ferrite core, 2-turn spiral
Air-core, 3-turn spiral
Process-compatible with interposer and inductor
Thermal stress, adhesion to under layer, Via- contact, ・・・
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The Third International Workshop on Power Supply on Chip 2012
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□ First trial of embedded inductor in glass/epoxy interposer
Glass-sub. (Hc=14 Oe)
Build up layer (Hc=19 Oe)
- 20 - 10 0 10 20 - 1
- 0 . 5
0
0 . 5
1
M / M s
Applied magnetic field H [kA/m]
Zn0.22Fe2.78O4
1 10 100 1000 0
10
20
30
40
50
60
Frequency f [MHz] Pe
rmea
bilit
y µr’,
µr”
Build up layer
Glass-sub.
µr’
µr”
Zn0.22Fe2.78O4
Surface of build up layer
Zn0.22Fe2.78O4 Random orientation
Build up layer (Epoxy/glass-filler)
Random grain-growth
Metal plane
Build up layer
Build up layer Zn - Fe ferrite film
Glass - epoxy core
Glass substrate (Corning 7059)
Columnar grain-growth
Zn0.22Fe2.78O4 (111) orientation
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□ First trial of embedded inductor in glass/epoxy interposer
Interposer with embedded inductor Top Zn-Fe ferrite core
Bottom Zn-Fe ferrite core
Photograph of Interposer with embedded inductor
Down !!
Metal plane Metal plane
Zn-Fe ferrite core, 2-turn spiral Air-core, 3-turn spiral
(HFSS, ANSYS)
1 10 100 0
1
2
3
4
5
Indu
cta
nce
L [n
H]
Calculated using HFSS
Frequency f [MHz]
Air-core, 3-turn spiral
Zn-Fe ferrite core, 2-turn spiral
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The Third International Workshop on Power Supply on Chip 2012
PowerSoc2012
□ First trial of embedded inductor in glass/epoxy interposer
□ First trial of large current inductor using CIP/epoxy composite core
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The Third International Workshop on Power Supply on Chip 2012
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140 µm 30 µm
35 µm
30 µm
30 µm
Top CIP/epoxy composite core
Bottom CIP/epoxy composite core
Glass-substrate
5 µ
m
Polyimide
Copper line Copper line
Top CIP/epoxy composite core 100 µm
Bottom CIP/epoxy composite core
Glass-substrate
A’
A
1000 µm
1000 µm 880 µm-square, 2-turn,
35 µm thick copper spiral coil on bottom CIP/epoxy
composite core
Formation of top CIP/epoxy composite core
Using 54 vol.%-CIP/epoxy composite core
Air core
1 10 100 0
2
4
6
8
10
Indu
cta
nce
L [
nH
]
Frequency f [MHz]
0
5
10
15
20
Qual
ity
facto
r Q
We are currently developing the CMOS-switch dc-dc converter integrated in LSI package ! !
Collaborating with
N. Matsushita Lab., Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Japan R & D Div., SHINKO ELECTRIC INDUSTORIES Co. Ltd., Nagano, Japan T. Sakurai Lab., Institute of Industrial Science, the University of Tokyo, Tokyo, Japan
VIN
L
Cout
RS VOUT
Load
I
WO
Controller
VIN
CMOS switch with optimal gate-width WO
VM
COUT
PMOS
NMOS
PMOS Driver
NMOS Driver
CMOS switch
Embedded inductor
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The Third International Workshop on Power Supply on Chip 2012
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□ Conclusion and future work
Spin Device Technology Center, Shinshu University, Nagano, Japan
Magnetic core power inductor for package-level power grid
・Zn-ferrite inductor embedded in glass/epoxy interposer ・Carbonyl-iron/epoxy core for large current inductor on package
Future work Package-level power grid will be demonstrated.
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The Third International Workshop on Power Supply on Chip 2012
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