10/8/2009 1

Material Trade-offs in Designing Ceramic Packages

Arne Knudsen

Kyocera America, Inc.October 2009

10/8/2009 2

Contents

• Package Design Process

• Material Selection Process and Cost trade-offs

• Package Fabrication Process

• HTCC - LTCC Comparison

• High frequency package design and simulation example

• Summary

10/8/2009 3

Package Design Process

Select Material &

Design

Define

Requirements

RF

Simulation

Package Layout for

other traces

Frequency &

Band Width

Device size &

Interconnect

I/O's

Hermetic

Acceptable?

Customer

Acceptance

Manufacture and Test

Package Performance

Package meet requirements

High Frequency

Application?

Dimensional Requirements

Yes

No

NO

No

YES

Board Details

CustomerDefined

Kyocera Defined

Diagnose

& ResolveNo

YES

FeNiCo

Heat Sink(Cu/Mo)

FeNiCo

Ceramic body

Thermal

Dissipation

10/8/2009 4

Typical Ceramic Material Properties

(1MHz) (2 GHz) (1MHz) (2 GHz)

A473 9.1 8.5 5 10 6.9 18 400 270 W, Mo, Thin Film

A440 9.8 – 24 – 7.1 14 400 310 W, Mo, Thin Film

A443 9.6 – 5 – 6.9 18 460 310 W, Mo

AO600 9 8.8 10 21 7.2 15 400 260 Cu-W

AN271 8.8 8.6 1 152 4.7 150 450 310 W, Thin Film

AN242 8.7 8.6 1 170 4.7 150 400 320 W, Thin Film

AN75W 8.8 8.9 4 51 4.8 76 430 320 W

GL550 5.6 5.6 6 9 5.9 2.0 200 110 Cu

GL560 6.0 6.0 5 17 6.2 1.5 200 91 Cu

GL660 9.4 9.6 2 17 6.2 1.2 200 100 Cu

GL771 5.3 5.2 (10GHz) 7 38 (10GHz) 12.3 2.0 175 75 Cu

DuPont 951** 7.8 7.8 15 5 5.8 3.3 320 120 Au, Ag, Mixed Metals, Resistors

DuPont 943** 7.4 7.4 <5 5.0 6.0 4.4 230 150 Au, Ag, Mixed Metals, Resistors

Ferro A6S** 5.9 5.9 12 12 >8 2.0 160 92 Au, Ag, Mixed Metals, Resistors

Ferro A6M** 5.9 5.9 12 12 7.0 2.0 170 92 Au, Ag, Mixed Metals, Resistors

MULLITE ML751 6.5 – 13 – 4.1 4.4 270 190 –

Air Fired

LTCC

Flexural

Strength (MPa)

ALUMINA

ALUMINUM

NITRIDE

LTCC

TAN δ δ δ δ (x 10 -4)

CERAMIC

MATERIAL

OPTIONS

ELECTRICAL THERMAL MECHANICAL

CONDUCTOR

MATERIALDIELECTRIC CONSTANT

Young's

Modulus of

Elasticity

(GPa)

CTE (x10 -6)

1/C (RT-400oC)

Thermal

Conductivity

(W/mK)

10/8/2009 5

Material Selection Depends on Several Factors

“Optimal”

manufacturable package design

Application

Physical Properties

Process variations

Tradeoffs

price

delivery

performance

Manufacturing Design Guidelines Simulation tools

Measurement (validation)

SMT packages

LTCC MCM

10/8/2009 6

Cost is function of Design, Materials and Manufacturing

Material

Design rules

Cost

$

Number of vias

Number

of

layers

Tolerances

Schedule

Size

Unique

processes

Tooling

Metals

Plating

Assembly

Simulation & Simulation &

ModelingModeling

10/8/2009 7

Ceramic Packages and Applications

10/8/2009 8

L-X-band: Low frequency, standard package materials and designs,

Often with embedded passives

K-band: Mix of LTCC and HTCC (narrow-band)

Challenging broad-band applications (OC-768)

W-band: Very difficult transitions, lossy

10/8/2009 9

N2 -Fired Ni plating - Not required

for air-fired LTCC

LTCC Process Flow is similar to HTCC, But Processes and Materials Vary

10/8/2009 10

HTCC Attributes:

• Pro– Robust and proven technology

– Automated production systems

– Mechanically & thermally superior to LTCC

– Less expensive

– Braze: CuAg (CuSil), AuSn, others

– Optimum Reliability

• Con– Cannot incorporate embedded resistors

– Lossy at high frequencies

– Limited dielectric constant, CTE

10/8/2009 11

Aluminum Nitride

Frequency (MHz)

tan

δ (

×1

0-4

) AN75W

AN242

250

200

150

100

50

01 10 100 1000 10000100000

0000

20202020

40404040

60606060

80808080

100100100100

120120120120

140140140140

0000 1111 2222 3333 4444 5555Time (sec)Time (sec)Time (sec)Time (sec)

Al2O3Al2O3Al2O3Al2O3

AN75WAN75WAN75WAN75W

AN242AN242AN242AN242

PKG:50mmSQ.CHIP:12.7mmSQ.Power:ca.25W

Junction Temperature (

Junction Temperature (

Junction Temperature (

Junction Temperature (℃℃ ℃℃)) ))

Piezoelectricity Thermal Conductivity-AlN vs. Al2O3

10/8/2009 12

Commercial Suppliers of LTCC Tape

– Dupont 951, 943, 9K7• Easier to process and fire

• Tight shrinkage tolerances

• Electrical performance similar to 92% Al2O3

– Ferro A6M

• Higher variation in shrinkage during firing.

• Lower loss, easier to design high frequency devices (>10 GHz)

• More difficult green processing

– Heraeus Heralock

• Controlled shrinkage

• Less-commonly used

10/8/2009 13

Cu-based LTCC Materials

• Kyocera-developed

• Custom formulations to meet specific applications

– Dielectric constant

– Thermal coefficient of expansion

– Flexural strength

• Nitrogen-fired, Ni-Au plating

• Non-brazeable

• Metal adhesion may be weak

• Excellent for filter designs

• Low insertion loss

10/8/2009 14

Pa

ste

Co

st

($/g

)

$46.00

$3.00

$0.70

$0.12

Du

Po

nt

951

Ky

oce

ra

Du

Po

nt

951

HT

CC

Metallization Cost Drives Package Price

Precious Metal Price not Market Driven

323% increase since 2001

10/8/2009 15

HTCC – LTCC Cost Comparison

LTCC is Performance-based Material

Proper Design in HTCC can achieve necessary performance objectives.

LT

CC

A

u

LT

CC

A

g

LT

CC

Cu

HT

CC

HT

CC

Average Volume Package

Price (Relative Scale)7

6

5

4

3

2

1

10/8/2009 16

Insertion Loss (Au Conductors on Ferro LTCC)Left: Simulating insertion loss with different surface roughnesses and comparing them with measurement data.

Right: Actual surface roughness observation with varied manufacturing process conditions.

Surface

Ink (Gold)

Ceramic

10/8/2009 17

LTCC has Better Performance with Thinner Substrates / Longer Conductor Paths at High Frequencies.How to read this graph: In the region right of the red curve the IL of A473 is more than 0.05 dB inferior to that of A6M for a microstrip line with L= 200

mils. The red curve may also represent 0.25 dB delta per inch. Similarly, the pink line for 0.50 dB delta per inch and the blue line for 1 dB delta per inch.Example: When a 15-mil thick substrate is used for 50-ohm system, A6M material should be 0.25 dB/inch better in IL than A473 at about 9.5 GHz.

50 ohm microstrip; .05 dB IL difference curve

0

2

4

6

8

10

12

14

16

18

20

0 10 20 30 40 50

Frequency (GHz)

su

bstr

ate

heig

ht (m

il)

.05 dB delta curve; L=50 mils

.05 dB delta curve; L=100 mils

.05 dB delta curve; L=200 mils

Insertion Loss Comparison (Simulation):

increasing delta IL

HTCC (Al2O3/W) vs. A6M

(LTCC/Au)

10/8/2009 18

What can be integrated?

• HTCC:– Inductors

– Caps to ~100 pF

– Couplers

– Filters

– Antennas

• LTCC:– Resistors

– Inductors

– Caps to ~100pF, embedded to 1k

– Filters

– Antennas

10/8/2009 19

Multilayer HTCC CapacitorsPrediction vs Results

• Al2O3 ceramic with W metallization

• Cross-sectioned to validate methodology

10/8/2009 20

HF Packages Require Electrical Modeling, Simulation Tools…

� Electrical Modeling, Simulation

– Frequency Domain:

� HFSS

• Ansoft Optimetrics

• Q3D Extractor

• Ansoft Designer

– Time Domain

� CST Microwave Studio

� Full-Wave SPICE – Ansoft

– Sigrity Speed2000 Power SI

– Eagleware – Filter Synthesis

– 2D

� Tx Line

� TLINE

� UIUC2D (stratified layers, finite ground planes)

Simulation

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

0 5 10 15 20 25 30

Frequency (GHz)

Re

turn

Lo

ss

(d

B)

S11-Ansoft

HFSS uses Maxwell’s equations: package model is meshed, and characterized in the frequency domain

Connectors for High Frequency Applications

10/8/2009 21

Thermal Modeling and Verification

� Thermal Modeling and Verification– Simulation

� ANSYS - 2 Seats

– Measurement� Laser Flash - material property

� IR Camera (ΦJC)

IR Camera

For ΦJC

Case 3 @ 6W: Minus Lid and Copper Slug

¼ FE Model

Temp ( C )

Actual

Package

FEM analysis to improve 2nd

level Reliability

10/8/2009 22

Material Characterization Capability is Critical for Failure Analysis

� Material Characterization & Failure Analysis Typical Tools:

– Instron

– Phillips ESEM XL30 - SEM 30x 100Kx

– Dilatometer

– X-ray diffraction

– DTA / TGA

– Olympus AX70 - Optical 10x to 1500x microscope

– Sonoscan CSAM300 - Ultrasonic 1x to 10xImage of Silver Dendrite

EDAX X-ray Spectra and MappingSEM

10/8/2009 23

T/R Modules (Transmit-Receive)

• High-Power Microwave

• Phased-Array Radar

• Coaxial Connector

• Compartments provide EM shielding between subcomponents

10/8/2009 24

Other High Reliability Programs

JSFJSF

Global HawkGlobal Hawk

F22F22

Stealth ShipsStealth Ships

AegisAegis

Ground RadarGround Radar

10/8/2009 25

RF Interconnect Design Strategy using Full-wave tools: Ansoft HFSS or CST MWS

Methodology

• Divide RF routing into a series of independent transitions.

– Board to package

– Internal to package

– Package to die

• Identify materials / design options

• Use HFSS or CST to model and optimize each transition

– Break large transitions into sub-models, solve, and optimize.

– Assemble sub-models and solve the entire RF path.

General approach• Short RF transitions.• Arrange vias and ground to inhibit RF reflections.• Re-arrange and shrink cavities to inhibit resonance.• Use coplanar structures for better isolation.• Employ appropriate design rules.

Tuning

Preliminary

Transition

Solid Model

Data Transfer

Simulation

10/8/2009 26

Example: Astrium TR module

The ENVISTAT ASAR Instrument Verification and Characterization, R. Torres, et al

Customer granted permission to

show slides of this design

10/8/2009 27

Original T/R Module

Discrete RF Packages, 1990’s

10/8/2009 28

Conceptual Sketch Started the Simulation Process

10/8/2009 29

Initial Physical Design…

…RF Transitions Defined

10/8/2009 30

Astrium X-band module

Cinch interface + GPPO connectors7 packaged dies on bottom

Self calibration circuitPolarized transmission vertical and horizontal

BGA-packaged ASIC

Antenna tile: 24 TR modules per tile

10/8/2009 31

Simulation Targets

Module Desired Performance

-60

-50

-40

-30

-20

-10

0

8 8.3 8.6 8.9 9.2 9.5 9.8 10.1 10.4 10.7 11 11.3

Frequency GHz

dB

Return Loss

Power Divider

Coupling

Isolation

3dB Power Divider17dB Coupler

LNA Isolation

RF Return Loss - S11

10/8/2009 32

Details: 11 individual design challenges

10. GPPO to Long Stripline

7&8. Calibration to GPPO

6. 3dB coupled line

5. Output to Cinch connector short and long versions4. 3dB coupled line

3. Polarization switches to Circulators

2. PA output

1. PA in

9. -16.5dB coupler calibration line

11. Overall combined model

10/8/2009 33

Details of one transition

10/8/2009 34

11 Port Model Results

LNA Isolation

Input/Output S11

3 dB Power Divider 17 dB Coupler

10/8/2009 35

Putting it all together….

24 modules/tile, 28 tiles/satellite

T/R module

Tile Control UnitPower Supply

Units1651

10/8/2009 36

Electrical

(RF loss)

Mechanical

(Braze joint

reliability)

Thermal Material cost Resistor

Alumina B A C B No

Med-loss LTCC B B D C Yes

Low-loss LTCC A D D D Yes

Aluminum nitride C B A C No

BeO (post-fire) C A A+ B No

The Best Ceramic Solution?

It depends

10/8/2009 37

1

10

100

1000

10000

100000

1000000

Wid

e -

X X

Wid

e -

X Ku

Wid

e -

Ku

Ka

Ku L S

Wid

e -

S

Wid

e -

X X

Ku

Ka

- N

arr

ow S

Wid

e -

X Ku

Ka

Ka

Wid

e -

X Ku Q W

Package Design plays a Significant roll in Meeting Required Specifications at High Frequencies

HTCC LTCC

AlNAl2O3

A - 440

Al2O3

A - 473

DuPont951

FerroA6M

Packag

es

Updated - June 2009

10/8/2009 38

High Volume T/R Module

Reprinted from Military and

Aerospace Electronics, May 2003.

10/8/2009 39

Conclusions

• Materials choice should be based on:

– Performance Requirements

– Manufacturability

– Cost Objectives

• No “best” material for all applications

• Simulation and validation are critical

10/8/2009 40

Kyocera Sales ContactsEastern Region

Boston: Bob Palumbo 508-651-8161New Jersey: Antonio Pagkalinawan 732-563-4379

Central RegionAustin, TX Ross Linker 512-809-0195Dallas, TX Lawrence Santos 972-234-2408Phoenix, AZ Katie Hanken 602-315-6664

Western RegionPortland, OR Scott Tse 503-526-6962San Jose, CA Scott Tse 510-257-0150

San Diego, CA John Hatakeyama 858-576-2764