LIQUID CRYSTAL POLYMER (LCP)
METALLIZATION
Feng Liu and Joseph Law
June 8
SUR/FIN 2022
Plating on Functional Plastics
Megatrends
❑ High Speed High Frequency
❑ Increased Functionality, Integration, & Miniaturization
❑ Electronic & Autonomous Vehicles
Telecom &
Data Center
Market Needs
❑ Signal Integrity & Reliability
❑ Thermal Management
❑ Reduced Weight and Design Flexibility
Automotive
Plating on functional plastics reduces weight, simplifies manufacturing,
and offers functions from connection, EMI shielding to thermal management
2
Liquid Crystal Polymer (LCP) Introduction
• LCP is a high melting point thermoplastic material, typically based on rigid rod-shaped aromatic
polyesters, with different types of reinforcement or fillers added to the polymer network
❑
❑
❑
❑
Glass fiber
Mineral (mica/talc/clay)
Carbon fiber
Conductive carbon black
• Other types of LCP based on amides, imides, and carbonates are also commercially available
Solid state
Molten state
Conventional
polymer
(ABS, PC…)
Molding
Random Coil
Liquid crystal
polymer (LCP)
Folded Structure
Molding
Liquid Crystal
Oriented Structure
Polymer chain
3
Why Plate LCP?
• The excellent mechanical, thermal and electrical properties of LCP make it a growing option
for many applications in automotive, telecom, HSHF circuits, and electronic connectors
❑ Good flowability in molding
❑ High dimensional stability
❑ Low moisture absorption
Comparison of selected properties: LCP vs ABS
ABS
LCP
2.0 – 2.6 GPa
11 – 24 GPa
Elongation at Break (%)
3.5 – 50 %
1.0 – 3.0 %
Heat Deflection Temp.
at 1.82 MPa
76 – 110 oC
240 – 270 oC
~ 0.05 – 1.8 %
0.02 – 0.05 %
❑ Low dielectric constant
Elastic Modulus
Moisture Absorption
(ASTM D570)
4
Challenges and Approaches in LCP Metallization
• LCP metallization seed layer can be achieved by sputtering,
lamination of metal foil with adhesives, or embedded catalyst
• An all-liquid approach offers reduced cost and flexibility to
complex design shapes, with some challenges to solve
Finishing layer
(e.g. Sn, Ni)
❑ Weak adhesion of LCP to plated metal seed layer
❑ Some types of fillers difficult to plate
❑ Molding conditions effect on plating
• DuPont TELEPOSIT™ 8000 approach focuses on achieving
❑ Required surface for strong metal adhesion
❑ Optimum catalyzation for full coverage, even on tough fillers
Electrolytic Cu or
full build-up e’less Cu
Seed metal layer (e’less Cu / Ni)
LCP substrate
5
TELEPOSIT™ 8000 LCP Metallization Process
TELEPOSIT™ 8000 LCP Metallization
Process
Function
TelepositTM 8010 Sweller
TelepositTM 8100 Conditioner G
Prepare the surface
TelepositTM 8200 Conditioner M
• Customer preference and patterning
technique determine the choice of
electroless Ni or Cu as seed layer
TM
Teleposit 8300 Conditioner
TelepositTM 8440 Catalyst
TelepositTM 8500 Accelerator
Activate the surface
and plate seed layer
TelepositTM 8600 Electroless Ni
OR TelepositTM 8700 Electroless Cu
TelepositTM 8800 Electrolytic Cu
Required finishing
• Filler type determines selection of
surface preparation and conditioner
• A strong, conductive and ductile
electrolytic copper is typical and
followed by the required finishing
Functional and protective
Finishing
6
Surface Preparation
• Traditional mechanical roughening (e.g. sand blasting) is not well controlled and is not a
fully 3D process
• All liquid process with TELEPOSIT™ 8000 LCP Metallization allows for processing of
complex parts and tuning of surface preparation for specific LCP types
LCP with glass fiber & mineral, 30%
Surface texture
Mineral filler
500X
Glass fiber
500X
Before Processing
After Teleposit™ 8000 Process Surface Preparation
7
Surface Preparation Process for LCP Metallization
Selection of surface preparation chemicals
and baths can be modified based on the
filler types in LCP
Surface
Preparation
LCP with
Glass
Fiber
LCP with
GF &
Mineral
LCP with
Mineral
TelepositTM 8010
Sweller
√
√
√
TelepositTM 8100
Conditioner G
√
√
TelepositTM 8200
Conditioner M
√
After sweller
√
After sweller and Conditioner
8
Optimization of Surface Preparation - Roughness
The Teleposit™ 8010 Sweller breaks down LCP polymer bonds without an additional oxidizer etch
• Surface morphology and roughness monitored by dwell time
As is
1X
1.5X
2X
2.5X
3X
Surface Roughness Ra (mm)
6
5
4
3
2
1
0
Dwell time
LCP with 30 % Glass Fibers and Mineral Fillers
9
Optimization of Surface Preparation - Adhesion
Excellent metal adhesion on LCP achieved via optimization of dwell time, process temperature, and concentration
TREATMENT TIME
0.5X
1X
1.5X
2X
2.5X
3X
Adhesion Test
of Seed Layer
(w/ 0.7 μm e’less Cu)
No
peel off
Cu peeled
off
Adhesion Test
of Seed and
Build-up Layers
Baking Test
(250 °C, 15min)
No
peel off
Blistering
Blistering
Blistering
Blister-free
Blister-free
Blister-free
Best Adhesion
10
Surface Preparation: Mechanical vs Chemical
Mechanical Sand Blasting
TELEPOSIT™ 8000 Process
Surface Morphology
Sa = 8.65 μm
Sa = 4.48 µm
Plated Metal Appearance
(Electroless Cu, Electrolytic Cu,
and Electrolytic Sn Finish)
Adhesion Tape Test
✓ Pass
✓ Pass
Baking Test (250˚C, 15 min)
✓ Pass
✓ Pass
Teleposit™ 8000 LCP Metallization provides good plated metal adhesion with lower surface
roughness than mechanical roughening
11
Activating the Surface
• TELEPOSIT™ 8000 Conditioner and Catalyst were
formulated to achieve uniform catalyst adsorption
• Uniform catalyst particles (2 – 5 nm) are very stable
• DuPont offers both colloidal and ionic Pd catalysts
• Even distribution on surfaces and inside complex
design shapes
• As a result, plated LCP samples have consistent
plating thickness distribution on the surface
2
1
3
4
5
Uniform catalyst adsorption
inside features
Plating thickness (µm)
• Broad compatibility with various substrates and filler
types
Uniform catalyst
particle size
3
2
1
0
1
2
3
4
5
Location
Even plating thickness distribution on the LCP surface
12
Plate Seed Layer
Both the Teleposit™ 8600 Electroless Ni and Teleposit™ 8700 Electroless Cu provide full and uniform
coverage for subsequent electroplating
Factor
Teleposit™ 8600 Electroless Nickel
Teleposit™ 8700 Electroless Copper
Deposit
Conductivity
• Lower than electroless Cu
• Requires a strike prior to subsequent
electroplate
• No strike required
Bath Life and
Control
• Typically long bath life
• Simple analysis and replenishment based on
[Ni] and pH
• Typically shorter bath life
• Replenish all components in ratio to [Cu] and
adjust by routine analysis
Environment
• EDTA-free
• Formaldehyde-free
• Cyanide-free
• Cyanide-free
• Contains formaldehyde* and EDTA
(*DuPont also offers ECOPOSIT™ XF-1000 Formaldehyde-free Electroless Cu)
13
Functional and Protective Finishing
• The electroplated finish depends on the function and assembly of the LCP substrate
• Provides strength, conductivity, ductility, and leveling
• Teleposit™ 8800 Copper provides the optimum performance for LCP applications
• Often applied over copper to prevent copper migration to the surface
• DuPont offers both traditional and boric acid free electroplating options
• Used as both an etch resist, or as a solder medium, for subsequent assembly
• Solderon™ Tin products offer all appropriate options
• Finishes that provide brightness, wear resistance, durability, corrosion resistance, or other
performance requirements may also be applied.
14
Conclusions
• LCP is an excellent material choice for applications in automotive, telecoms, electronic
connectors and high-speed, high frequency circuits
• TELEPOSIT™ 8000 LCP Metallization Process provides uniform plating and good adhesion
with a smoother surface roughness than traditional mechanical roughening
15
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