Design rules Flex xF and TWINflex® xF – Ri Application in accordance with IPC 2223 Use A: Flex-to-install No UL marking These design rules apply to: flexible circuit boards with 1 to 4 copper layers on flexible polyimide material, optionally with glued mechanical stiffener Examples (shown without coverlay or solder mask): 1F-Ri: 1 layer with glued stiffener 4F: Flexible multilayer with 4 layers, standard vias Nomenclature: F = flexible, Ri = rigid Basic information • Please comply with general standards, such as IPC or IEC • Please take note of 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 resist mask* • Essentially, marking print is not possible. • Flexible circuit boards must be dried before they are assembled. Further information about this is available in our Internet pages. * • Copper removal is required in ground or reference layers for drying. Recommendation: Copper openings 0.3 mm per 1 mm length of copper • Flex-to-install bending radius: Installation Use A in accordance with IPC-2223 up to 90° bending angle: o 1 or 2 copper layers: 10 x total thickness (IPC-2223 section 5.2.4.2) o More than 2 copper layers: 20 x total thickness (IPC-2223 section 5.2.4.3) o For use in more demanding conditions, please contact us • We will be happy to create the optimal delivery panel for you (best price!) * Andreas Schilpp All documentation can be found online at: www.we-online.com/flex 11.04.2016 Page 1 of 3 Design rules Flex xF and TWINflex® xF – Ri Application in accordance with IPC 2223 Use A: Flex-to-install No UL marking Material specifications Material Standard Spec. sheet Description Application Flexible base IPC-4204 11 Polyimide adhesiveless Microvia, hand soldering material IPC-4204 2 Polyimide with glue Rigid material IPC4101 21 FR4 Tg 135°C Standard Flex solder green, photosensitive Standard mask JIS C 5012/ IPC-SM840 Coverlay IPC-4203 Polyimide covering film 25 µm, acrylic or epoxy glue (multilayer process) Optional in place of flex solder mask (surcharge) 1/2 Layer stack-up Standard layer stack-ups, see www.we-online.com/flex Standard design 1. Polyimide 50 µm adhesiveless, flexible PCB total thickness without stiffener 0.1 mm to 0.3 mm (depending on number of layers) 2. Base Copper thickness inner layers 18 µm, exterior layers 9 µm + electroplating 3. Flexible photosensitive solder resist green 4. Standard vias, plating thickness in accordance with IPC6013 5. Outline lasered or milled, smallest milling diameter 1.6 mm. V-scoring not permitted! 6. Solderable surface ENIG (electroless Nickel – immersion Gold) 7. Packaged in ESD shrink wrap Andreas Schilpp 11.04.2016 Page 2 of 3 Design rules Flex xF and TWINflex® xF – Ri Application in accordance with IPC 2223 Use A: Flex-to-install No UL marking C A B TOP 1 2 Cross-section: 2F - Ri F = flex Ri = rigid Optional mechanical stiffener, glued BOTTOM a: single Coverlay opening larger than pad b: window opening Description Symbol Technical standard - Distance copper to outline Number x of copper layers (xF) C Thickness of flexible material (polyimide, LCP on request) 50 µm - Thickness of cold-bonded stiffener made of FR4 material Thickness of glue for stiffener 0.1 – 0.5 mm CL (solder mask) CL (coverlay) W (solder mask) W (coverlay) “ZIF” Advanced requirements ≥ 300 µm 1-4 Minimum clearance of copper pad with photosensitive flex solder mask Minimum clearance of copper pad with coverlay (milled, lasered) Minimum bridge width photosensitive flex solder mask Minimum bridge width coverlay (milled, lasered) 50 µm 70µm circumferential 450µm circumferential 70µm circumferential 500µm Avoid vias in bending area! ZIF contacts thickness tolerance Usage of microvia technology: possible with 2F and 4F (staggered via): A (HDI) Minimum pad diameter for microvia B (HDI) Finished Hole diameter lasered microvia 75 / 100 / (125)µm 0.5 – 0.8 mm ± 0.05 mm 350µm 300µm ≈ 100µm Further specifications available on request, contact us: [email protected] Andreas Schilpp 11.04.2016 Page 3 of 3