45NKWOVEN KEVLAR REINFORCED LAMINATE AND
PREPREG
45NK

isawovenKevlar® aramid

fiber

reinforced

multifunctional epoxy laminate andprepreg systemengineered to provide in-plane CTE values as low as 6ppm/°C for compatibility with leadless alumina ceramic chip
carriers (LCCC’s) and other low expansion SMT devices
where control of laminate expansion is critical for solder joint
reliability.
45NK exceeds the requirements of IPC
4101/50 (Type AFG).
Features:• High Tg (170°C) for improved reliability through process andin-use• Low Dielectric Constant 3.9• High modulus (19 x 106 psi) p-aramid woven fiber
reinforcement with CTE of -4 ppm/°C provides superior X-Y
CTE of 5-7 ppm/°C• Process compatible with conventional high Tg multifunctional
epoxy systems• 100% Organic resin/reinforcement system is suitable for laserdrilling• RoHS/WEEE compliant• UL-94 V0 exceeds IPC 4101 /50 requirements
Typical Applications:• SMT Board Designs using LCCC’s or other low expansion chip carriers (See Figure 1)• SMT Designs requiring both low in-plane CTE and laser drillingTypical Properties:
Property45NK
UnitsValue

Test Method-3.9

IPC TM-650 2.5.5.3
IPC TM-650 2.5.5.9

Dissipation Factor@ 1 MHz@ 1 GHz
Volume Resistivity-0.016

IPC TM-650 2.5.5.3
IPC TM-650 2.5.5.9

C96/35/90

MΩ-cm

1.3 x 107

IPC TM-650 2.5.17.1

1. Electrical Properties
Dielectric Constant (may vary with Resin %)@ 1 MHz@ 1 GHz

E24/125
Surface Resistivity
C96/35/90
E24/125
Electrical Strength (typical)
Dielectric Breakdown
Arc Resistance

MΩ-cm
MΩ
MΩ
Volts/milkVsec

IPC TM-650 2.5.17.1
3.2 x 107
750 min

IPC TM-650 2.5.17.1
IPC TM-650 2.5.17.1
IPC TM-650 2.5.6.2
IPC TM-650 2.5.6
IPC TM-650 2.5.1

2. Thermal Properties
Glass Transition Temperature (Tg)
TMA
DSC°C°C

170

IPC TM-650 2.4.24
IPC TM-650 2.4.25

Decomposition Temperature (Td)
Initial
5%
T260
T288
T300
CTE (x,y)CTE (z)< Tg°C°C
minminminppm/°C

5-7 ppm/ °C

IPC TM-650 2.3.41
IPC TM-650 2.3.41
IPC TM-650 2.4.24.1
IPC TM-650 2.4.24.1
IPC TM-650 2.4.24.1
IPC TM-650 2.4.41

ppm/°C75

IPC TM-650 2.4.24> Tg
z-axis Expansion (50-260ºC)

ppm/°C%

2252.8IPC TM-650 2.4.24
IPC TM-650 2.4.24

lb/in (N/mm)
lb/in (N/mm)

66

IPC TM-650 2.4.8
IPC TM-650 2.4.8.2

lb/in (N/mm)

6

IPC TM-650 2.4.8

Young’s Modulus
Flexural Strength
Tensile Strength

Mpsi
kpsi (MPa)kpsi (MPa)4.0

IPC TM-650 2.4.18.3
IPC TM-650 2.4.4
IPC TM-650 2.4.18.3

Compressive Modulus
Poisson’s Ratio (x, y)

kpsi (MPa)-0.2

ASTM D-695
ASTM D-3039

Water Absorption
Specific Gravity%g/cm30.8%
1.5

IPC TM-650 2.6.2.1
ASTM D792 Method A

Thermal Conductivity

W/mK

0.22

ASTM E1461

Flammability

ClassV0UL-94

3. Mechanical Properties
Peel Strength to Copper (1 oz/35 micron)
After Thermal Stress
At Elevated Temperatures
After Process Solutions

4. Physical Properties

Results listed above are typical properties, provided without warranty, expressed or implied, and without liability. Properties may vary, depending on design and application. Arlon reserves
the right to change or update these values.

Availability:Arlon Part
NumberFabric StyleResin ContentVolatiles

Nominal Pressed

45NK257

3500 Kevlar

57 ± 3%

0.5% max

0.004”

45NK262

3500 Kevlar

62 ± 3%

0.5% max

0.0045”

Recommended Process Conditions:
Process inner-layers through develop, etch, and strip using standard industry practices. Usebrown oxide on inner layers. Adjust dwell time in the oxide bath to ensure uniform coating.
Bake inner layers in a rack for 60 minutes at 225°F - 250°F (107°C - 121°C) immediately
prior to lay-up.
Vacuum desiccate the prepreg for 8 – 12 hours prior to lamination.
Lamination Cycle (vacuum press is preferred – see notes, below):1)Pre-vacuum for 30 minutes

2)

Control the heat rise to 8°F - 12°F (4°C - 6°C) per minute between 130°F and 230°F (55°C and110°C)
Panel Size

Pressure

Pressure (Vacuum Press)

incm

psi

kg/sq cmpsi

kg/sq cm

12 x 1840 x 46

275

19150

10.5

16 x 1830 x 46

350

25170

12.3

18 x 2446 x 61

400

28200

14.13)

Product temperature at start of cure = 360°F (180°C).

4)

Cure time at temperature = 90 minutes

5)

Cool down under pressure at ≤ 10°F/min (5°C/min)

Process Notes:
Kevlar® fabric compresses and distorts under pressure, more so than E Glass, which dictates the useof lower lamination pressures. The use of an autoclave or vacuum assist lamination makes the use oflower pressure possible. Typically the pressures used under vacuum should be about 50% of thoseused for standard press lamination e.g. 12” x 18” (30 cm x 45 cm) panel non-vacuum 300 PSI(2 kg /cm2) versus vacuum 150 PSI (10.5 kg/cm2).

45NK
Optimal processing requirements may vary depending on specific equipment and operating conditions. These recommendations are offered only as a starting point.

The use of a low pressure “kiss cycle” until the resin has melted will minimize stresses on the material,and should improve registration. The resin melts at 160°F (71°C) and gels at 340°F (170°C). The
transition from low pressure to high pressure should occur in the lower end of this window (165 175°F/74-79°C). A cure cycle of 360°F (182°C) for 90 minutes should give a Tg of 175°C. A properly
cured laminate is essential for minimizing processing problems in subsequent process operations.
Drilling: Drilling techniques that work well with laminates made with E Glass may produce snags andtears in Kevlar®. Basic parameters of 450 SFM (135m/min) and 1 mil (27 micron) chip load seem towork well. It is necessary to check for proper drill geometry and quality, as well as checking the holequality at set-up before proceeding with drilling the complete panel.
Hole Cleaning: A vapor hone/blast with 300-350 grit Aluminum Oxide to remove debris and loose
fibers is advantageous prior to plasma etch.
Prebake Prior to Plasma Etch: A prebake process prior to plasma etch of 250°F (121°C) for 90 to120minutes is recommended to remove any absorbed moisture.
Plasma Etch: A plasma etch process that has worked on epoxy Kevlar®to achieve positive etch-back is
as follows:
1. Prebake at 250°F (121°C) for
2.Plasma treatment:90 to 120 minutes. RF Power – 2 kw.Gas mixture - CF4 (Freon™) 70%O2(Oxygen)
30%.Flow rate - 750 cc / minute each. Electrode temperature - 250°F to300°F (121 –149°C).Duration - 20 to 30 minutes. Purge - O2 100%.
Prebake Prior to Electroless: A prebake process of 250°F (121°C) for 60 to 90 minutes prior toelectroless copper process is recommended to remove absorbed moisture.
Electroless Copper and Copper Plating: Standard practices for electroless deposition have been used
as well as a double pass to aid in the encapsulation of any protruding fibers. A heavier copper plating(possibly 2to 2.5 mils/50 - 63 microns as opposed to 1 to 1.5 mils/25 - 38 microns) may be desirable
to improve thermal management and to resist barrel cracking due to the higher Z axis expansion oflaminates reinforced with Kevlar® fabric.
Routing: The use of sharp cutters is more important with Kevlar®fabric than with glass fabric. Feedrates may need to be reduced by 10 to 25% to minimize the incidence of frayed edges.
Solder Reflow: A prebake process of 250°F (121°C) for 90 to 120 minutes prior to any solder reflow
process is recommended.

45NK

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Tel (86) 512-6269-6966
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