Design Rules Flex-Rigid 1F xRi

Design rules
Flex-rigid 1F – xRi
Application in accordance with IPC 2223: Flex-to-install
UL labelling in accordance with UL94 and UL796 possible
These design rules apply to:
flex-rigid circuit boards with 1 copper layer on flexible polyimide material, externally located.
Example: 1 copper layer
Example: 8 copper layers
Basic information
• Please comply with general standards, such as IPC or IEC
• Please note the useful information and tips in the WE Flex-Rigid Design Guide *
• Please see the WE Basic Design Guide for rules for line widths, spacing, via and pad sizes, solder
mask*
• Lift-off areas - attention: NO copper layout below the flex and NO vias permitted!
• Flex-rigid circuit boards must be dried before they are assembled and soldered. Further information
about this can be found on our Internet pages. *
• For the drying, copper openings in ground or reference layers are needed.
Recommendation: Copper openings: 0.3 mm per 1 mm length of copper (up to 70µm Cu thickness):
• Flex-to-install bending radius: Assembly bending requirement according to IPC-2223:
o
1 copper layer: Bending radius at least 10 x total thickness (IPC-2223, Section 5.2.4.2)
o
For use in more demanding conditions, please contact us
• We will be happy to create the optimal delivery panel for you (best price!)
*
All mentioned documents can be found online at: www.we-online.com/flex
Andreas Schilpp
17.05.2016
Page 1 of 3
Design rules
Flex-rigid 1F – xRi
Application in accordance with IPC 2223: Flex-to-install
UL labelling in accordance with UL94 and UL796 possible
Material
Standard
Spec. Sheet
flexible base
IPC-4204
11
material
2
Polyimide adhesive-
Microvia, hand-soldering
Polyimide with glue
JPCA-BM03
IPC4101
128
IPC-4101
preg
Standard
Polyimide with glue
(92,94,127)
LowFlow Pre-
Application
less
IPC-4204
Rigid material
Description
128
(92 /93 /94/95
FR4 Tg 150°C, filled;
Standard
low-halogen
Epoxy Prepreg
Standard
Tg150°C
/122/125/127)
Soldermask
IPC-SM840
green, photosensitive
Standard lacquer in the
rigid areas
Flexible sol-
JIS C 5012/
dermask
IPC-SM840
green
Partially in the flex area
or over the entire area of
flex side
Coverlay
IPC-4203
1/2
Polyimide coverlay
Optional covering of flexi-
film, acrylic or epoxy
ble area in place of flexi-
glue
ble lacquer (surcharge)
Standard stack-up drawings see www.we-online.com/flex
Standard design
1. Polyimide 50 µm with glue, epoxy glue, PCB total thickness 0.8 mm to 1.55 mm
2. Copper layer thickness inner layer 18 µm
3. Low-Flow Prepreg
4. Flexible soldermask green on flex side, not flex side or optional all rigid areas with standard green
solder resist epoxy
5. Standard vias
6. Smallest milling diameter 1.6 mm
7. Solderable surface ENIG
8. Packaged in ESD shrink wrap
Combination with microvia technique and buried via technique possible:
see WE HDI Design Guide for microvias through dielectric 100µm thick.
Andreas Schilpp
17.05.2016
Page 2 of 3
Design rules
Flex-rigid 1F – xRi
Application in accordance with IPC 2223: Flex-to-install
UL labelling in accordance with UL94 and UL796 possible
Cross-section: 1F – 3Ri
F = flexible
A
Ri = rigid
B
TOP = flex layer
1
2
3
H
4
BOTTOM
C
D
TOP view 1F – xRi
Symbol
A
B
C
D
E
F
G
G
H
K
“K”
“ZIF”
Technical
standard
Description
Line widths and spacings
Minimum via pad diameter teardrops recommended 
Final diameter of continuous vias
Spacing, Cu – outer layer to flex-rigid transition coupling (bottom)
Spacing, Cu – inner layer to flex-rigid transition coupling
Distance of conductor to the flexible contour
Spacing, exposed Cu – outside of flex-rigid transition coupling
Flexible lacquer: Spacing, exposed Cu to flex-rigid transition coupling (top)
PI coverlay: Spacing, exposed Cu to flex-rigid transition coupling
(top)
Length of the flex area
Minimum recess width directly at the flex area
Outline manufacturing of flex area: No scoring permitted!
ZIF contacts thickness tolerance
Advanced
requirements
see WE Basic Design Guide!
see WE Basic Design Guide!
see WE Basic Design Guide!
≥ 300 µm
≥ 500 µm
≥ 300 µm
≥ 300 µm
≥ 1000 µm
800µm
≥ 1500 µm
1000 µm
≥ 5mm
1.6 mm
≥ 2.5 mm
1.0 mm
± 0.05 mm
Enhanced specifications on request – please. Contact us at: flex@we-online.de
Andreas Schilpp
17.05.2016
Page 3 of 3