curamik® CERAMIC SUBSTRATES
DBC technology
DESIGN RULES Version 12/2014
Content
1. Geometric properties
3. Quality
1.01. Available ceramic types / thicknesses........................... 03
3.01. Solderability – wetting on metallization...................... 10
1.02. Copper thicknesses (standard)...................................... 03
3.02. Thick wire bondability on metallization...................... 10
1.03. Total dimensions master card....................................... 04
1.04. Max. usable area............................................................ 04
4. Physical properties
1.05. Delivery form.................................................................. 04
4.01. Thermal conductivity..................................................... 10
1.06. Tolerances of single parts outside dimensions............ 04
4.02. Electrical resistivity of ceramic.................................... 10
1.07. Available material thickness combinations.................. 04
4.03. Dielectric constant........................................................ 10
1.08. Copper free perimeter...................................................06
4.04. Dielectric loss................................................................. 11
1.09. Conductor dimensions width / spacing.........................06
4.05. Dielectric strength (DC voltage) of ceramic.................. 11
1.10. Sidewall of etched pattern............................................06
4.06. Electrical conductivity of copper surface...................... 11
1.11. Mismatch copper pattern front/back............................ 07
4.07. Copper peeling strength ................................................ 11
1.12. Etching tolerance........................................................... 07
4.08. Application temperature............................................... 11
1.13. Flatness (layout related)................................................ 07
4.09. Bending strength (bare ceramic)................................... 11
1.14. Chip-off at ceramic edge................................................. 07
4.10. Fracture toughness (K1c)................................................12
1.15. Tolerance of total thickness (ceramic + copper)............ 07
4.11. Young‘s modulus (bare ceramic)......................................12
4.12. Coefficient of linear thermal expansion (CTE)...............12
2. Additional design features
2.01. Platings over entire surface..........................................08
2.02. Copper surface...............................................................08
2.03. Dimples..........................................................................08
2.04. Lifetime with/without dimples....................................09
2.05. Solder stop.....................................................................09
2.06. Holes and laser cut outlines.........................................09
Available ceramic materials
Al 2 O 3
HPS *
AlN
Alumina
Alumina
(9% ZrO2 doped)
Aluminium
Nitride
* The HPS products are subject to patent restrictions in some countries.
Based on zirconia toughened alumina (ZTA).
1. Geometric properties
1.01. AVAILABLE CERAMIC TYPES / THICKNESSES
Material
ceramic thicknesses mm
Al2O3
HPS
AlN
0.25
0.32
0.38
0.5
0.63
1.00
AI203 other thicknesses on request
HPS
ZrO2 toughened Al2O3 with 9% content
AIN
other thicknesses on request
1.02. COPPER THICKNESSES (STANDARD)
Al2O3
0.127 mm
0.2 mm
0.25 mm
0.3 mm
0.4 mm
HPS
0.127 mm
0.2 mm
0.25 mm
0.3 mm
0.4 mm
AlN
0.127 mm
0.2 mm
0.25 mm
0.3 mm
0.4 mm
0.5 mm
0.6 mm
curamik® CERAMIC SUBSTRATES I Design Rules DBC I Version 12/2014
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1.03. TOTAL DIMENSIONS MASTER CARD
as fired 138 x 190.5 mm ± 1.5%
1.04. MAX. USABLE AREA
laser scribed 127 x 178 mm + 0.2 mm / - 0.05 mm @ d(ceramic) ≤ 0.63 mm + 0.3 mm / - 0.05 mm @ d(ceramic) > 0.63 mm
Note When using master cards we recommend to use laser scribed material
due to the 1.5% average firing tolerance of ceramic (as fired).
1.05. DELIVERY FORM
Master card
with or without laser scribing; defect parts inked
Single parts
minimum dimension 15 x 15 mm edge length, smaller on request
1.06. TOLERANCES OF SINGLE PARTS OUTSIDE DIMENSIONS
+ 0.2 mm / - 0.05 mm @ d(ceramic) ≤ 0.63 mm + 0.3 mm / - 0.05 mm @ d(ceramic) > 0.63 mm
Note Single parts laser scribed
1.07. AVAILABLE MATERIAL THICKNESS COMBINATIONS
Al2O3
copper thickness mm
ceramic thickness mm
0.127
0.2
0.25
0.3
0.25
0.32
0.38
0.5
0.63
1.00
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curamik® CERAMIC SUBSTRATES I Design Rules DBC I Version 12/2014
0.4
available
standard material
combinations
HPS
ceramic thickness mm
copper thickness mm
0.127
0.2
0.25
0.3
0.4
0.5
0.6
available
0.25
standard material
combinations
0.32
0.38
AlN
copper thickness mm
ceramic thickness mm
0.127
0.2
0.25
0.3
0.4
available
0.38
standard material
combinations
0.5
0.63
1.00
Note The copper thickness difference of front side to back side shall not exceed 100 µm.
The copper thickness may not be larger than the ceramic thickness (except HPS).
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1.08. COPPER FREE PERIMETER
A
Cu-thickness
A
≤ 0.2 mm
≥ 0.2 mm
≤ 0.3 mm
≥ 0.25 mm
≤ 0.4 mm
≥ 0.3 mm
≤ 0.5 mm
≥ 0.35 mm
≤ 0.6 mm
≥ 0.4 mm
A
Copper
Ceramic
Copper
A = Copper free perimeter
Note Metallization is measured at the interface of ceramic and copper. Final perimeter depend on ceramic thickness and manufacturing tolerances such as etching
or lasering.
1.09. CONDUCTOR DIMENSIONS WIDTH / SPACING
Pitch
Cu-thickness (d)
Conductor dimensions
width / spacing (W)
Min. Pitch
0.127 mm
typ. 0.35 mm
0.7 mm
0.2 mm
typ. 0.4 mm
0.8 mm
0.25 mm
typ. 0.45 mm
0.9 mm
0.3 mm
typ. 0.5 mm
1.0 mm
0.4 mm
typ. 0.6 mm
1.2 mm
0.5 mm
typ. 0.7 mm
1.4 mm
0.6 mm
typ. 0.8 mm
1.6 mm
Copper
W
W = Width
d = Cu-thickness
Note Metallization is measured at the interface of ceramic and copper. Upper width
of conductors on Cu-layout side could be smaller (see sidewall of etched pattern).
1.10. SIDEWALL OF ETCHED PATTERN
≤ ½ Cu-thickness
Note Metallization is measured at the interface of ceramic and copper.
The sidewall of the etched pattern (the outside edge of a pad or conductor)
has a paraboloid shape. When indicating the width of a pad or conductor,
the width at the bottom side of the etched pattern (at the ceramic) is typically used. The nature of the etching process results in the effective width
of a pad or conductor at its top surface being reduced by a maximum of the
copper thickness (d).
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curamik® CERAMIC SUBSTRATES I Design Rules DBC I Version 12/2014
d
Ceramic
≤½d
Copper
Ceramic
d = Cu-thickness
d
1.11. MISMATCH COPPER PATTERN FRONT/BACK
M
A
M ≤ 0.1 mm
Copper
Ceramic
Copper
Note Metallization is measured at the interface of ceramic and copper. The
difference of copper-free perimeter between the front and back should be
defined as < 0.5 mm.
A
M
A = Layout side / Bottom side
M = Mismatch copper pattern
1.12. ETCHING TOLERANCE
A
Cu-thickness
tolerance
≤ 0.2 mm
typ. ± 0.15 mm
≤ 0.3 mm
typ. ± 0.20 mm
≤ 0.4 mm
typ. ± 0.25 mm
Copper
Ceramic
A = pad/conductor
Note Metallization is measured at the interface of ceramic and copper. The
etching tolerance is always symmetric to the center axis of the pad/conductor.
1.13. FLATNESS (LAYOUT RELATED)
Requested flatness of single DBC substrates or master cards cannot be guaranteed in
advance due to specific design influences of the circuit. A flatness (not 100% inspected)
can only be specified after design definition and sample delivery with initial sample
test report.
1.14. CHIP-OFF AT CERAMIC EDGE
Length
Width
Depth
max. 1 x ceramic thickness
max. ½ x ceramic thickness
max. ½ x ceramic thickness
W
L
W = Width
D
L = Length D = Depth
1.15. TOLERANCE OF TOTAL THICKNESS (CERAMIC + COPPER)
+ 7 % / - 10 %
copper thickness ≤ 0.4 mm
Note Tolerance of total thickness for grinded DBC single parts or master cards
can only be specified after sample delivery with initial sample test report.
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2. Additional design features
2.01. PLATINGS OVER ENTIRE SURFACE
Electroless Ni
3 – 7 µm (8% ± 2% P)
Electroless Ag
0.1 – 0.6 µm
Electroless NiAu
Ni: 3 – 7 µm (8% ± 2% P)
Au Class A: 0.01 – 0.05 µm
Au Class B: 0.03 – 0.13 µm
Electroless NiPdAu *
Ni: 3 – 7 µm (8% ± 2% P)
Pd: 0.05 – 0.15 µm
Au Class A: 0.01 – 0.05 µm
Note Partial plating and other thicknesses on request. * samples available
2.02. COPPER SURFACE
Roughness
Rmax = 50 µm; Ra ≤ 3 µm; Rz ≤ 16 µm
Note Lower roughness on request.
2.03. DIMPLES
Copper
thickness
08
Dimple area Dimple
- e1 row diameter
-d-
Corner dimple
diameter
- d2 -
d
0.127 mm
0.50 mm
0.35 mm
0.35 mm
0.50 mm
0.20 mm
0.60 mm
0.45 mm
0.45 mm
0.65 mm
0.25 mm
0.70 mm
0.50 mm
0.45 mm
0.70 mm
0.30 mm
0.80 mm
0.60 mm
0.50 mm
0.80 mm
0.40 mm
1.00 mm
0.70 mm
0.60 mm
1.00 mm
0.50 mm
1.20 mm
0.90 mm
0.75 mm
1.20 mm
0.60 mm
1.40 mm
1.20 mm
1.20 mm
1.40 mm
curamik® CERAMIC SUBSTRATES I Design Rules DBC I Version 12/2014
d2 (corner
dimple)
Dimple pitch
- M-M -
M-M
Copper
Ceramic
e 1 r ow
2.04. LIFETIME WITH/WITHOUT DIMPLES
Measurement conditions -55 °C up to 150 °C shock testing
ceramic
Cu
layout side
ceramic
thickness
Cu
back side
cycles without
dimples
Al2O3
0.3 mm
0.32 mm
0.3 mm
> 65
HPS
0.3 mm
0.32 mm
0.3 mm
> 110
AlN
0.3 mm
0.63 mm
0.3 mm
> 35
Note curamik internal tests with curamik test layout
With dimples, lifetime can be increased by a factor of 10.
Lifetime
Number of Thermal Cycles
1800
1600
1400
1200
1000
800
600
400
without
dimples
200
with
dimples
0
Al2O3
HPS
AlN
2.05. SOLDER STOP
standard solder stop
high temperature solder stop *
Width
min. 0.4 mm
tolerance ± 0.2 mm
min. 0.4 mm
tolerance ± 0.2 mm
Mismatch solder stop line
(center) to layout (center)
± 0.2 mm
± 0.2 mm
Temperature
resistance
≤ 288 °C / 10 sec.
≤ 400 °C / 5 min.
Note In case of mismatch between Cu pad and outside edge, the etching tolerance is to be
considered. Higher/ longer temperature exposure only possible at customer’s own risk.
Solder stop is available for all platings except Au-platings. * samples available
2.06. HOLES AND LASER CUT OUTLINES
Minimum hole diameter 1 mm, smaller on request.
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3. Quality
3.01. SOLDERABILITY – WETTING ON METALLIZATION
Soldering conditions
on Cu surface
SnCu3ln0.5 - Preform ≥ 95 % wetting,
forming gas (5 % H2, 95 % N2) and vacuum
3.02. THICK WIRE BONDABILITY ON METALLIZATION
300 µm aluminum wire AlH11
Shear speed 500 µm/s
Shear height ≤ 30 µm
Shear force ≥ 1000 cN
≥ 50 % aluminum residue on DBC after shear test
4. Physical properties
1
4.01. THERMAL CONDUCTIVITY
Al2O3
24 W/mK @ 20 °C
HPS
26 W/mK @ 20 °C
AlN
170 W/mK @ 20 °C
4.02. ELECTRICAL RESISTIVITY OF CERAMIC
> 1014 Ωcm @ 20 °C
4.03. DIELECTRIC CONSTANT
10
Al2O3
9.8 @ 1 MHz
10.0 @ 1 GHz
HPS
12.5 @ 1 MHz
9.0 @ 1 GHz
AlN
9.0 @ 1 MHz
7.5 @ 1 GHz
curamik® CERAMIC SUBSTRATES I Design Rules DBC I Version 12/2014
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Values from literature
4.04. DIELECTRIC LOSS
Al2O3
0.0003 @ 20 °C, 1MHz
HPS
0.001 @ 20 °C, 1MHz
AlN
0.0005 @ 20 °C, 1MHz
4.05. DIELECTRIC STRENGTH (DC VOLTAGE) OF CERAMIC
> 20 kV/mm
4.06. ELECTRICAL CONDUCTIVITY OF COPPER SURFACE
58 x 106 S/m @ 20 °C
4.07. COPPER PEELING STRENGTH
≥ 4.0 N/mm @ 50 mm/min @ Cu-thickness 0.3 mm on Al2O3
Note According to curamik internal tests.
4.08. APPLICATION TEMPERATURE
-55 °C up to +850 °C depending on atmosphere and time
Critical at H2 with >400 °C
4.09. BENDING STRENGTH (BARE CERAMIC)
Al2O3
> 450 N/mm2
HPS
> 600 N/mm2
AlN
> 350 N/mm2
Note According to curamik internal tests. Bending strength of DBC can be more than double
of the above mentioned, depending on Cu-thickness and layout.
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4.10. FRACTURE TOUGHNESS (K1c)
Al2O3
3.8 – 4.2 MPa√m
HPS
4.5 – 5.0 MPa√m
AlN
3.0 – 3.4 MPa√m
4.11. YOUNG‘S MODULUS (BARE CERAMIC)
Al2O3
340 GPa
HPS
310 GPa
AlN
320 GPa
4.12. COEFFICIENT OF LINEAR THERMAL EXPANSION (CTE)
ceramic αceramic
substrate
Al2O3
6.8 ppm/K @ 20 °C – 300 °C
5% to 30% higher (dependent on copper thickness)
HPS
7.1 ppm/K @ 20 °C – 300 °C
5% to 60% higher (dependent on copper thickness)
AlN
4.7 ppm/K @ 20 °C – 300 °C
5% to 30% higher (dependent on copper thickness)
αDBC surface = αceramic + (αCu – αceramic )
∙
ECu ∙ dCu
ECu ∙ dCu + Eceramic ∙ dceramic
Copper
Ceramic
Copper
αCu = 16.5 αceramic = see list above
α = coefficient of thermal expansion
E = young´s modulus
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curamik® CERAMIC SUBSTRATES I Design Rules DBC I Version 12/2014
d = width mm
dCu
dceramic
dCu
The information contained in this document is intended to assist you in designing with Rogers’ Power Electronics Solutions
Materials. It is not intended to and does not create any warranties, express or implied, including any warranty of merchantability or fitness for a particular purpose or that the results shown in this document will be achieved by a user for a particular
purpose. The user should determine the suitability of Rogers curamik products for each application. The Rogers logo, the
curamik logo and curamik are licensed trademarks of Rogers Corporation.
© 2014 Rogers Corporation. All rights reserved.
This specification is not subject of updating.
Version 12/2014 issued in April 2014.
Issued by Bernd Lehmeier / Nico Kuhn
Approved by Tomas Block
curamik® CERAMIC SUBSTRATES I Design Rules DBC I Version 12/2014
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Rogers Germany GmbH
Am Stadtwald 2
92676 Eschenbach
Germany
Phone +49 9645 92 22 0
Fax +49 9645 92 22 22
www.rogerscorp.com/pes