The Third International Workshop on Power Supply on …pwrsocevents.com/wp-content/uploads/2012-presentations/session-7/7...Spiral inductor Si CMOS LSI Siliconinterposer (Flip chip)

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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□ 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


Examples of CMOS-switch DC-DC converter using air-core inductor


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.

6

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 ! !


PowerSoc2012

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.


□ 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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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


Interposer

Embedded inductor

Capacitor

Drive

r

Internal Circuit

PWM controller


Embedded inductor

Capacitor D

rive

r Internal Circuit

PWM controller


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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□ 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


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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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□ 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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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]


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


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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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


Process-compatible with interposer and inductor

Thermal stress, adhesion to under layer, Via- contact, ・・・

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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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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]


Zn-Fe ferrite core, 2-turn spiral

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□ First trial of large current inductor using CIP/epoxy composite core

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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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□ Conclusion and future work


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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PowerSoc2012

Documents

The Third International Workshop on Power Supply on …pwrsocevents.com/wp-content/uploads/2012-presentations/session-7/7...Spiral inductor Si CMOS LSI Siliconinterposer (Flip chip)