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LTCC – What is it and Where is
it Going?
A Personal View
Dr Peter Barnwell
President, IMAPS North America
peter@barnwell.org.uk
Peter Barnwell
Circuit Materials Division
LTCC – What and Why
Peter Barnwell
Circuit Materials Division
What is it?
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Low Temperature Co-fired Ceramic
Manufactured by:• Tape casting unfired ceramic material with
binder
• Printing conductor & other patterns
• Laminating
• Firing at around 850 Celsius
Peter Barnwell
Circuit Materials Division
LTCC Process
"Green Tape"
Collating
Blanking
Laminating
Via
Punching
Co-Firing
Via Fill
Post Printing
Post Firing
Conductor
Print
Trimming
&
Electrical
Test
Final Test
© 2000 Midas Vision Systems, Inc.
Peter Barnwell
Circuit Materials Division
LTCC Key Points
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Parallel processing:• High yield
• Quick turnaround
• Volume manufacture
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High layer count readily available
Integrated components:• Microwave circuit structures
• L, C & R
Peter Barnwell
Circuit Materials Division
LTCC Market Growth to 2000
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Initially a military market
Volume applications developed in 1990’s:• Europe – automotive
• US - disk drive module – now finished
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2000 Applications
• Wireless packages (power amplifiers, radio, VCO,
synthesizers, mixed signal packages)
• Bluetooth modules
• Components - antennae; baluns; filters
• Other microwave modules
• Automotive (engine, steering, and transmission
control, sensors)
Peter Barnwell
Circuit Materials Division
LTCC Manufacturing
Infrastructure - 2002
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C-MAC acquires Scrantom Engineering & Thomson
VS - April 1999. Major expansion in 2000
Disk drive amplifier market created CTS’s
infrastructure – CTS now telecomm & automotive
National moves facility to Irvine, CA and expands
Kyocera and Coors diversify from HTCC to LTCC.
Kyocera acquire Vispro in 2000
Several companies –in both Europe (Selmic, Via,
Epcos) and US (Amitron; Barry; CPT) developing
LTCC facilities
Asia – major developments
Peter Barnwell
Circuit Materials Division
Ceramic Interconnect
Initiative - CII
Brings together circuit manufacturers with suppliers of materials,
equipment, substrates and services to work to advance the ceramic
interconnect industry.
Peter Barnwell
™
> 40 companies participating
™
Communication
™
Education
™
Roadmaps
™
Homepage
Circuit Materials Division
Benefits of Ceramic
FEATURES
Hi Q / Low Loss / Low Tf
Precisely Defined Properties
Circuit Density / Integral
Components
Environmental Robustness &
Stability
Thermal performance
High K
BENEFITS
Performance, Talk Time, Smaller
IC’s = COST
Ease of Design, Time-to-market =
COST
Size, functionality, performance
= COST
Performance, Reliability
= COST
Size, Reliability = COST
Small size microwave = COST
AND – Loves Lead Free!
Peter Barnwell
Circuit Materials Division
Vertical Integration in Packaging
A Paradigm Shift
# of Passives: 200
Assumptions:
Comp. Value: 20pF/20nH
Comp Size: 3 mm Sq
Q Value:
30 - 100
# Layers:
8
Area:
25 X 25 mm
Cost Savings:
Peter Barnwell
> $8.00
Circuit Materials Division
Why bury components?
Active
Components
Inductance and Coupling
Several in the
X - Y space of one
Peter Barnwell
Circuit Materials Division
LTCC - A Key Automotive Technology
•
•
•
•
working temperature up to
155°C
high vibration stress up to 50g
direct engine mountability
high packaging density (Thick
Film -> LTCC)
• good thermal conductivity high power dissipation
• max. power density
• Rth-values
1W/mm²
...4 K/W
• buried components
• environment friendly
• high innovation rate
Peter Barnwell
Circuit Materials Division
COST ($ /in2/layer)
Cost Gap Narrows
MicroVia
HDI PWB
LTCC
ML PWB
PWB
Peter Barnwell
Year
‘99
Circuit Materials Division
Substrate
Test
Substrate
Test
LTCC is:
Half the Size
80% the Cost
Assembly
Passives
ICs
Assembly
ICs
Bluetooth Cost Comparison - LTCC Vs. FR4
Passives
100%
FR4
80%
60%
40%
20%
Source: Ray Brown
IEEE/MTTS 2000
0%
ICs
Peter Barnwell
Passives
Assembly
LTCC
Test
Organic
Substrate
Module
Circuit Materials Division
Bluetooth Module
Peter Barnwell
Circuit Materials Division
Where is the Technology
Now?
Peter Barnwell
Circuit Materials Division
LTCC
z
Benefits:•
•
•
•
•
•
z
Parallel processing
High yield
Quick turnaround
Three dimensional
Good power handling
Excellent microwave performance
Drawbacks:•
•
•
•
Peter Barnwell
Shrinkage on processing
Dimensional variation
Reduced number of parts per tile
Warpage
Circuit Materials Division
Materials properties
z
A range of materials offering:• Permittivity from 6 to 9.1
• Loss tangents in the range 10-3 up
• Full range of conductor pastes – gold,
silver, solderable conductors
• Limited buried component capability
• Shrinkage in all directions on firing – 12 to
16%
• Line definition – 100 micron by printing
Peter Barnwell
Circuit Materials Division
Manufacturing Status
z
z
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Tile sizes typically in region of 6 to 8 inch
square
Punching normally sequential mechanical
Simple printing techniques
Very limited integrated passives
Peter Barnwell
Circuit Materials Division
So – What are the New
Technologies?
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Photo conductors
Buried passives:• High K tape
• Resistors
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Lower permittivity and loss
Constrained sintering:–
• zero x & y shrinkage
• Many advantages
Peter Barnwell
Circuit Materials Division
Critical properties for electrical
performance of LTCC
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Relative permittivity - εr
Loss tangent – tan δ
Resonant frequency vs. temperature – Tf
Conductor resistance
Surface roughness
Line resolution and edge precision
Control of parameters with process & batch
Peter Barnwell
Circuit Materials Division
Line Losses - Silver Conductor
All Lines 0.635 mm Wide, 50 ohms
Impedance, Identical Conductor
Material
Cavity 2.4
GHz
Tan δ x 10-3
Line Loss dB/mm
@ 2 GHz
99.5% Alumina
0.65
0.003
LTCC 1
3.8
0.004
LTCC 2
2.0
0.0035
LTCC 6 – CT2000
1.7
0.0033
Minimal Difference Between Dielectrics
Peter Barnwell
Circuit Materials Division
So – What Does This Mean?
• Conductor dominates loss - requires:• High density & high conductivity
• Precise geometries
• Smooth surface
• LTCC dielectric precision important - requires:• Precise Relative Permittivity - εr
•
•
•
•
•
Peter Barnwell
Precise geometries & shrinkage
Relatively Low Loss - Tan δ ≈ 10-3
Low Tf < 10 ppm/°C – for resonant structures
Simple processing
Low cost
Circuit Materials Division
HeratapeTM CT2000 Key Points
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Low price
Thin tape available – 2 mil green
Excellent thickness control - +/- 2%
Highest performance silver conductors – competitive
cost
Excellent dielectric properties:• Precisely defined εr = 9.1 +/- 0.1
• Low Tf - ≈ 10 ppm/°C
• Low loss - ≈ 10-3 – Q ≈ 1,000
z
Smooth surface – 0.25 micron
Peter Barnwell
Circuit Materials Division
Insertion Loss (dB)
Temp. Coefficient of Resonant Frequency (Tf)
Low Tf
Material
at 80 C
High Tf
Material
at 80 C
At 25 C
Low Tf is
Critical for
Filtering
and Freq.
Generation
Circuits
Frequency
For CT2000 Tf <10 ppm/C
For FR4 Tf = 80 ppm/C
Other LTCC 40 to 50 ppm/C
Peter Barnwell
Circuit Materials Division
50 Micron Patterned Lines
on LTCC
Direct printed on
LTCC
Peter Barnwell
Heraeus
TC2301PI
photoimaged on
LTCC
Circuit Materials Division
Constrained Sintering The HeraLock® Option
Peter Barnwell
Circuit Materials Division
HeraLock® Benefits
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Needs no extra processing
Virtually zero x & y shrinkage
Very precise dimensional control
Fires flat
Cavities readily available
Allows novel structures
Peter Barnwell
Circuit Materials Division
Precise dimensional control:90.2% shrinkage
9Tight shrinkage variation – 140ppm
918” width available
Positional Tolerance vs Panel Size
30
Standard LTCC, Free Sintered ± 0.2%
25
PLAS w/ Sacrificial Constraint Layers ± 0.12%
HeraLock® HL2000, Free Sintered ± 0.0042%
20
Positional
15
Tolerance (mil)
10
5
0
0
5
10
15
Format size (in)
Peter Barnwell
Circuit Materials Division
Large format size…
7 in
11 in
Outstanding shrinkage control on a large panel size…
Peter Barnwell
Circuit Materials Division
100% Coverage Ground-planes…
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Internal or external
zCompared
to grid
structures:
9Higher conductivity
9Better isolation
2”
9Easier designs
9NO localized
camber
Peter Barnwell
Circuit Materials Division
Precision cavity structures…
Undistorted Channels
Narrow slots
Non-shrink IC cavities
Peter Barnwell
Circuit Materials Division
Optoelectronic Application
Fibre buried in HeraLock®
Peter Barnwell
Circuit Materials Division
Cost Model:
Move from 8” to 12” panel in HeraLock®
RF (Power Amp)
z
Labor
Overhead/Depr.
Materials
8” panel
100%
100%
100%
Gross Margin*
x%
12” panel
30%
30%
85%
3x%
Automotive
Labor
Overhead/Depr.
Materials
8” panel
100%
100%
100%
Gross Margin*
x%
12” panel
30%
35%
81%
4x%
* assumes constant unpopulated part selling price
HeraLock can allow lower module pricing, therefore increasing competitiveness
Peter Barnwell
Circuit Materials Division
Where is it Going?
A Difficult Question!
Peter Barnwell
Circuit Materials Division
Major Restructuring –
LTCC was making its breakthrough just as
recession hit
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National & C-MAC facilities for sale –
caused by parent companies
concentrating on core business
Massive Chinese investment in facilities
Many companies holding back on
investment
Peter Barnwell
Circuit Materials Division
Market Size?
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Impossible to answer!
Market measured in $ value of finished
LTCC substrates
Paumonok says $757 million in 2002,
going to $833 million in 2003. $1,885
million in 2007.
A significant and growing technology
Peter Barnwell
Circuit Materials Division
Major LTCC Opportunities
• Microwave:• Modules
• Components
• Automotive
• Power
Other LTCC Opportunities
•
•
•
•
MEM’s
Fuel cells
Sensors
Etc…….
Not just a circuit technology!
Peter Barnwell
Circuit Materials Division
Conclusions
LTCC to be of great significance and potentially the
dominant ceramic circuit technology
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US manufacturers face questions:•
•
•
•
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Can they handle high volume market?
Need higher margin (lower volume?) products
Need to be design intensive.
Go offshore for volume production?
Similar trends in Europe – DT Microcircuits
Japanese very significant – Murata, Kyocera, TDK
Continued growth in many countries in Asia – China in
particular
Design in to be the key factor for large scale uptake
LTCC to be dominated by component manufacturers?
Peter Barnwell
Circuit Materials Division