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: [email protected] Andreas Schilpp 17.05.2016 Page 3 of 3