Embedded passives –Recent Advances and Opportunities

From PSMA Phase III Report

P M Raj, Himani Sharma, Teng Sun, Robert Grant Spurney, Rao Tummala

3D Systems Packaging Research CenterGeorgia Institute of Technology

Slide 2

CONFIDENTIAL

Outline

Need for embedded passives

Recent Advances– Magnetics:

o Material advances and options

o Low-frequency and high-power – nanocystalline and amorphous flakes

o Medium-frequency – medium power: Integrated metal flake composites

o High-frequency, high power density – thin nanomagnetic films

o Emerging opportunities

– Capacitors

o Low-voltage, integrated capacitors

o Medium-voltage integrated capacitors

o High-voltage, high-temperature capacitors

o Emerging opportunities

– LC integrated modules

Summary

Slide 3

Need for Embedded Passives

• High power density with advanced materials and designs

• Short PDN path: Reduce the need for decoupling

• Reduced impedance• Higher efficiency• Miniaturized modules

Discrete Inductors

Component Density (/cc)

Inte

rco

nn

ect

ion

Le

ngt

h

Mo

du

le T

hic

kne

ssPCB

SMT Discrete inductors• Large Height • Large foot-print

Substrate embedded passives• Smaller Height• Small foot-print

1 mm

10 mm

100 mm

1 mm

10 mm

200 mm

5 mm

1 mm

10 100 1000

IC

Inductor Capacitor

Slide 4

Magnetic Material Advances and Options

ThicknessMicrons

CoercivityA/m

Resistivitym Ohm cm

SaturationFlux (Tesla)

Permeability

Mn,Zn ferrites >100 3-5 10,000 0.6 5000

Nanocrystalline and amorphous flakes

>15 3 110 1.2 15000

Electroless thinfilms 3-5 10-20 100 1 <<1000

Plated thin films 2-100 20-80 35 1.3 ~1000

Flake composites 25-500 100-200 10,000 0.8 100-150

Nanomagnetic films 1-10 10 200-300 1.5 200-500

Low-Frequency, High-Power

Medium-Frequency, Medium-Power

High-Frequency, High Power Density

Slide 5

Low-Frequency - High-Power Magnetics

Ferrite 3C90: 500 kHz: 0.1 T peak; 700 mW/cc; 1 MHz; 0.02 T; 70 mW/cc;

Ferrite 3F5 MnZn: 1 MHz; 0.02 T; 30 mW/cc

Sumida’s ferrite: 1.5 MHz; 0.02 T; 37 mW/cc 1 MHz; 0.02 T; 70 mW/cc; 200 kHz; 0.1 T; 250 mW/cc

Vitrovac (Co67 Fe4 B11 Si16 Mo2) amorphous flakes:100 kHz; 0.1 Tesla, 30 mW/cc; 100 kHz; 0.2 Tesla: 200 mW/cc;

Hitachi metals: Finemet - FT-3L and FT-3M:20 kHz; 0.1 Tesla; 2 mW/cc20 kHz; 0.2 Tesla; 15 mW/cc20 kHz; 1 Tesla; 300 mW/cc

Co

re L

os

s m

W/c

c

1

0 Field (Tesla) 0.10.01 1

10

100

1000

10000

Slide 6

Medium Frequency – Medium Power: Inductor Advances

Sumida PSI2: Inductor in package molding

Virginia Tech: Inductor in PCB Substrate

Tyndall

Taiyo-Yuden – Inductor in package

4X increase in current-handling with metal compacts compared to ferrites

Better thermal, shielding,

High current-handling and efficiency

PCB-embedded ferrite and metal flake composites

Thin magnetic films and coupled inductor designs

2.8% increase in efficiency with 3-5 Amp current

Efficiency of a 61.7% power inductor at 91.7%

Slide 7

Medium frequency – Medium PowerSubstrate-Embedded Metal-Flake Composite Sheets

Nitto Denko Corporation

Substrate

Polymer insulation Magnetic sheets

Copper winding

IC IC

v vv

Laminate substrate

Copper winding

Magnetic film

Magnetic film

µ’

µ”

µ’

L/Rdc of 20 nH/milliohm; Current handling of 1 Amm2

Slide 8

Substrate

v

Polymer insulation

Copper winding Magnetic paste

IC IC

v v

Magnetic Core Inside Substrate Cavities

100μm

Hot-press magnetic particles or flakes into cavities inside laminate cores;

Wiring plated with standard organic laminate panel processes

µ’

µ”

Filler 1

Filler 1

Filler 2

Filler 2

One-side core

Air core

Two-side with polymer adhesive

Two-side with magnetic adhesive

Solid - SimulationDotted: Measurements

Slide 9

High-Frequency – High Power-Density

• Peak Q Factor > 20 @ ~100MHz• Peak Inductance Density ~300nH/mm2• L/RDC >200nH/Ω for L > 100nH• L/RDC of 120nH/Ω for L ~ 10nH• Current Density exceeding 12A/mm2 for coupled inductors• Saturation Current exceeding 1.5A for single inductors• Cross wafer inductance variability σ < 3%• Other Devices in development:• Transformers, improved inductor designs

• Material sample thickness = >40um • High deposition rate – high throughput and low cost• IC or glass substrate- compatible• Deposition thickness capability up to 50um • μr= 200, Bsat= 1.3 T, Q @ 5 MHz>90, Q@ 20 MHz=30 • 0.5 microhenries; Isat of 2 Amp on 6 inch;• Toroid and solenoid inductors

Rel

ativ

e P

erm

eab

ilit

y

Ur’’

Ur’

Frequency (MHz)

FERRIC

MAXIMµ’

µ”

Slide 10

Opportunities for Embedded Inductors

Thick nanostructured or amorphous films with low coercivity, high resistivity and soft magnetic properties:

Sputtered films: Good combination of properties but thin

Bulk synthesis approaches: Poor frequency stability

New approaches to get nanostructures and low losses but with thickfilms

Coupled inductors: with multiphase switching topologies, DC currents can be made to flow in opposite directions:

Cancel DC magnetic fields

Enhance current-handling

Introduce permanent DC fields in the opposite direction

Create artificial antiferromagnetic materials

Slide 11

Silicon TrenchPRC Thin-film

TantalumMLCC

Discrete or Wafer- or Panel-formed capacitors

Performance Parameters MLCC Silicon Trench Ta capacitors

Capacitance density 20 µF/mm3 10 µF/mm3 20-30 µF/mm3

Thickness 125 - 500 µm 500 µm 50-75 µm

ESR 5-10 mΩ.× µF 50 mΩ × µF 50 mΩ × µF

Frequency stability >100 MHz 10-100 MHz 10-100 MHz

Leakage current 0.1 µA/µF 0.1 µA/µF 0.1 µA/µF

Integration Die-side or landside

assembly/embedding

Silicon- integrated Wafer or package-

embedding

Slide 12

Land-side on-Si capacitors for integrated fan-out packaging

1 × 0.5 mm footprintLocated underneath info-POP supported by extra PCB layer

Deep trench capacitor structure

• Up to >500 nF/mm2 density• Superior VCC and TCC• Comparable ESR to MLCCs• Thickness as low as 100 µm

Deep Trench Land-Side Inserted Si Capacitors (TSMC)

Slide 13

Wafer-Formed Nanoelectrode Capacitors

Silicon Die

1.19 µF/mm2

at 1 MHz 1.09 µF/mm2

at 1 MHz

1.15 µF/mm2

at 1 MHz1.34 µF/mm2

at 1 MHz

65°C/95%RH for 500 hours

65°C/95%RH for 1000 hours

ICC

L

IC

C CL

Discrete power module

Integrated power module

Slide 14

Capacitor Integration Process Flow

Paralyene C

CVD

II. Lamination on Si

Vacuum laminator

III. Planarization

I. Passivation

15 µm ABF

100 µm ABF

IV. Via drill

a. Desmearing

b. Electroless Cu seed layer

c. Photolithography

d. Electroplating

e. Microetching

Capacitor foil

V. Metallization

UV or CO2

Laser

Slide 15

Package-Embedded High-Voltage Capacitors (KEMET)

Etched Aluminum Anode

Resin with fillers for lamination

Polymer, carbon ink, silver ink cathode layers

• Capacitors can be patterned onto transfer

release film

• Arrayed sheets

• Individual taping

• Terminals formed by copper cladding and

plating

Copper terminal

350 µm

Etched Al foil capacitors to package

48 V Power Converters

Thickness reduction and more

effective use of capacitance volume

Slide 16

Package-Embedded Thinfilm Capacitors

High permittivity compared to film dielectric;

Operation up to 150° C

GT-PRC DuPont

Delphi/Argonne National labs

Large-area polymer or metal

roll-to-roll compatible process

Applications:

• Isolators

• Embedded decoupling

capacitors

Thin ceramic film decoupling

capacitors in organic

package substrates;

1-1000 MHz

20 nF/mm2

Slide 17

Package-Embedded Thinfilm Capacitors (TFC)

Fujitsu

Doubleside integration of decoupling capacitors;

High-frequency noise suppression

Integration and reliability characterization

Slide 18

Inorganic-Organic Hybrid Dielectric

10 100 1k 10k 100k 1M0

5

10

15

20

25

30

_CNET25gDMF_NoHCl_delay 5K_1

_CNET25gDMF_NoHCl_delay 5K_2

_CNET25gDMF_NoHCl_delay 5K_3

_CNET25gDMF_NoHCl_delay 5K_4

tan_CNET25gDMF_NoHCl_delay 5K_1

tan_CNET25gDMF_NoHCl_delay 5K_2

tan_CNET25gDMF_NoHCl_delay 5K_3

tan_CNET25gDMF_NoHCl_delay 5K_4

Frequency (Hz)

Pe

rmittivity

0.0

0.2

0.4

0.6

Lo

ss ta

ng

en

t

0 100 200 300 400 500 600 700 800 900

60

70

80

90

100

De

riv

ati

ve

we

igh

t (%

/oC

)

Re

sid

ua

l w

eig

ht

(%)

Temperature (oC)

pH 1.5

pH 3

pH 4.8

pH 6.5

2-Cyanoethyl

Trimethoxysilane

(CNETMS)

Permittivity ~20 @1kHz Surface roughness:

0.25 nm

Thermal stability: < 300°C Dielectric strength: < 650 V/mm for

1.2 mm; < 1000 V/mm for films >

300nm

Films processed on a variety of

substrates (Si wafer, ITO-PET, Al-Mylar)

1) Kim, et al, J Mater. Chem., DOI: 10.1039/C7TA06750J. 2) Kim, et al., Adv. Energy Mater. 2015, 5, 1500767, DOI: 10.1002/aenm.201500767.

3) Kim, et al., ACS Appl. Mater. Interfaces 5, 1544-1547, 2013.

Slide 19

High-Voltage Capacitors

Polymer film caps ECI HT1

CDE 550C Aluminum Caps

KEMET Ni BME C0G (Comm.Grade)

TDK CeraLinkPLZT Ceramic

Advanced electrodes and dielectrics

mF/cc 0.085- >6 0.6-0.012 5.5-2 10

V 600-2400 200-500 500-3000 500-900 400

ESRm

60 16-228 5 4 5

Irms 5.2 5-31 24 12.5

Temp 125 105 125 150 105

Slide 20

Opportunities for Embedded Capacitors

High-voltage isolation:

High-permittivity and high-voltage dielectrics: PLZT, calcium zirconate

5000 V isolation with power transfer

Embedded film and discrete capacitors:

– MLCC that power processor chips with power module right under the chip (200 W in 100 mm2 or 2 W/mm2 )

High-density wafer- or package-integrated capacitors (3 – 400 V):

Tantalum film capacitors with porous electrodes

Etched foil capacitors

Copper film capacitors with porous electrodes

BST

LNO

High-density Thinfilm capacitors on Si

Embedded capacitors and film inductors

High-surface area electrodes with conformal dielectrics

Etched foil Capacitors

Slide 21

LC Integrated Substrates

• Cross section with metallized capacitor vias Top view of LC integrated circuit

Inductors

capacitors

• Frequency range: 5-140 MHz• Power handling: 1 W/mm2

• Leading-edge thin capacitors embedded in the laminate• Thin embedded inductors with magnetic composite films

C

LInductor and Transformer layers

Capacitor layer

GaN IC GaNRDL

SubstrateIC

3D power packaging with embedded actives and passives

Slide 22

Summary

Magnetics:

Advanced materials and designs leading to higher volumetric densities and smaller form-factors

Amorphous and nanocrystalline ribbon flakes - low frequency

Metal-flake composites – medium frequency

Sputtered and thin plated films – high frequency

Capacitors:

Advanced large-area fabrication of high-density film capacitors

Thin and area-integrated - eliminate pick-and-place

LC-integrated substrates for panel-embedded IVRs