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Technology and design rules for flexible printed circuits

Downloads
NameInfoVersionDateTypeSizeDownload
Technology - Flexible Printed Circuits (94.34 KB, PDF) 1.2-O26/5/2025PDF94.34 KB
Layer Stack-Ups - Flexible Circuit Boards - Rev 4.0 (82.44 KB, PDF) 4.0-O24/11/2024PDF82.44 KB
Suggestions - Flexible Printed Circuits - Excess Length Design (124.21 KB, PDF) 1.3-O27/1/2026PDF124.21 KB
Baking of Flexible- and Rigid-flexible Printed Circuits before Assembly (386.04 KB, PDF) 1.3-O21/10/2024PDF386.04 KB
 

Design Rules

Options and Characteristics - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Quantity 1 piece to 1 m² total area from 1 piece to mass production
Number of layers 1 to 2 layers up to 6 layers
Material thickness 65 µm or 45 µm respectively 25 µm to 0.30 mm
Copper thickness (base) 18 µm or 28~35 µm*
*2layer standard starting from 18 µm base copper, plated up to ~28 µm
5 µm, 9 µm, 12 µm, 18 µm, 28~35 µm*
*2layer standard starting from 18 µm base copper, plated up to ~28 µm
Material colour beige/fawn beige/fawn
Base material Polyimid with epoxy adhesive adesive-less polyimide (PI), polyethylen (PET)
Operating temperature around 120 °C up to around 200 °C (Tg 260), adesive-less polyimide (PI)
Copper type no selection Elektrolytic deposit (ED) or rolled annealed (RA)
Silk print layer none, Top none, top, bottom, double sided
Solder mask colour cover lay, yellow green solder mask
Cover lay yellow polyimide yellow, black or white polyimide
Combination solder mask & cover lay possible possible
Silk print colour white black, blue, yellow, white, red
Via-Filling (no copper lid) possible (with cover lay) possible (with cover lay)
Stiffener for standard ZIF/LIF connector 0.30 mm +/-0.05 mm several thicknesses, FR4 or polyimide
3M-adhesive possible possible
E-Test possible possible
Plugging Plugging (with copper lid, e.g. for „via-in-pad“ technology) not possible not possible
Peelable mask not possible possible (stiffeners)
Chamfering/beveling not possible not possible
Surface finish i mmersion gold (ENIG) i mmersion tin, i mmersion gold (ENIG), i mmersion silver, OSP
Connector gold plating not possible possible
Long term tempering not possible possible
Maximum FPC size 1 and 2 layers 230x580 mm² 230x580 mm²
Maximum FPC size 4 and 6 layers not possible 220x320 mm²
Lead time options 1- and 2 layers FPCs 5WD, 7WD, 9WD, 12WD, 17WD, 22WD from 3WD
Lead time options 4- and 6 layers FPCs not possible from 10WD
Routing not possible not possible
V-Cut / scoring not possible possible, inside fixture/stiffener
Jump scoring not possible not possible
Punching (soft tooling) standard possible
Punching (hard tooling) not possible possible
Hand Cut not possible possible
Hand cut & soft tooling combination not possible possible
Counter sink drills / tapped holes not possible not possible
Special multilayer stack-ups not possible possible
Panel production - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
V-Cut / scoring panel not possible possible
V-Cut - punching panel (combination) not possible possible
Multi Panel (more than one 1 layout on a panel) not possible possible
Panel setup (chosen by Leiton) possible possible
Panel setup (according to drawing) not possible possible
PTH-drills (plated drills) - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Smallest Drill 5 µm to 18 µm (final diameter) not possible 0.15 mm
Smallest Drill 28~35 µm (final diameter) 0.25 mm 0.15 mm
Smallest Drill 70 µm (final diameter) not possible 0.20 mm
Smallest annular ring 5 µm to 18 µm not possible 0.10 mm
Smallest annular ring 28~35 µm 0.15 mm 0.10 mm
Smallest annular ring 70 µm not possible 0.15 mm
Possible drill sizes up to 5.5 mm in 0.05 mm steps up to 5.5 mm in 0.05 mm steps
drills >5.5 mm punched punched
Smallest hole-to-hole distance for 0.2 mm to 2.0 mm drill diameter (outer edge to outer edge) 0.50 mm 0.40 mm
Smallest hole-to-hole distance for 2.05 mm to 5.5 mm drill diameter (outer edge to outer edge) 0.60 mm 0.50 mm
Intersecting drills not possible replaced by punching
Half open drills on PCB edge (Half open PTH) not possible possible
NPTH-drills (non-plated drills) - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Smallest drill size (final diameter) 0.40 mm 0.30 mm
Possible drill sizes 0.40 mm to 5.5 mm in 0.05 mm steps 0.30 mm to 5.5 mm in 0.05 mm steps
Copper clearance / distance to copper 0.25 mm 0.20 mm
Drills >5.5 mm punched punched
Smallest distance from drill to outer edge 0.60 mm 0.50 mm
Smallest hole-to-hole distance for 0.2 mm to 2.0 mm drill diameter (outer edge to outer edge) 0.50 mm 0.40 mm
mallest hole-to-hole distance for 2.05 mm to 5.5 mm drill diameter (outer edge to outer edge) 0.60 mm 0.50 mm
Intersecting drills not possible replaced by punching
NPTH drills in copper area (without clearance) not possible (copper will be cleared by min. 0.25 mm) on explicit notification
Blind Vias - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Smallest blind via (final diameter) not possible 0.20 mm
Smallest Aspect-Ratio not possible 1
Smallest annular ring not possible 0.15 mm
Buried Vias - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Smallest buried via (final diameter) not possible 0.20 mm
Slots (non-plated) - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Inner slots NPTH by punching or hand cut Hard tool punching
Smallest inner slot NPTH from 1.0 mm up, punching or by hand cut from 0.5 mm up, hard tool punching
Smallest radius (inner corners) NPTH right angle acute angle
Slots (plated) - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Inner slots PTH not possible possible
Smallest inner slot PTH not possible from 0.5 mm hard tool punching
Edge plating (outer edge) not possible possible
Special outline paths with plating (inner) not possible possible
Smallest radius (inner corner, final) PTH not possible right angle
Smallest annular ring not possible 0.15 mm
Copper Layers (outer) - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Smallest trace 5 µm not possible 0.03 mm
Smallest trace 9 µm not possible 0.06 mm
Smallest trace 18 µm not possible 0.09 mm
Smallest trace 28~35 µm 0.10 mm oder 0.15 mm 0.10 mm
Smallest trace 70 µm not possible 0.20 mm
Smallest trace-to-trace distance 18 µm not possible 0.09 mm
Smallest trace-to-trace distance 28~35 µm 0.10 mm oder 0.15 mm 0.10 mm
Smallest trace-to-trace distance 70 µm not possible 0.20 mm
Smallest drill-pad diameter 0.55 mm 0.40 mm
Smallest copper clearance to inner edges (slots) 0.25 mm 0.20 mm oder 0.0 mm (plated)
Smallest copper clearance to outer edges 0.25 mm 0.20 mm oder 0.0 mm (metallisiert)
Smallest copper clearance to outer edges (V-Cut) not possible 0.50 mm
Copper Layers (inner) - Multilayer Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Smallest trace 5 to 9 µm not possible 0.04 mm
Smallest trace 18 µm not possible 0.09 mm
Smallest trace 28~35 µm not possible 0.10 mm
Smallest trace 70 µm not possible 0.20 mm
Smallest trace-to-trace distance 5 to 9 µm not possible 0.04 mm
Smallest trace-to-trace distance 18 µm not possible 0.09 mm
Smallest trace-to-trace distance 28~35 µm not possible 0.10 mm
Smallest trace-to-trace distance 70 µm not possible 0.20 mm
Smallest drill-pad diameter not possible 0.40 mm
Smallest copper clearance to outer edges not possible 0.30 mm
Smallest copper clearance to inner edges (slots) not possible 0.35 mm
Smallest copper clearance to drills not possible 0.30 mm
Solder Mask - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Smallest solder mask web (straight) 0.10 mm 0.10 mm
Smallest solder mask web (round) 0.08 mm 0.08 mm
Smallest size around copper pad 0.05 mm <0 mm
Smallest text lines 0.25 mm 0.25 mm
Cover Lay (punched / drilled / lasered) - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Smallest rectangular pad (clearance) 5x5 mm 2x2 mm
Smallest cover lay web (straight) 5.0 mm 2.0 mm
Smallest cover lay web (round) 3.0 mm 1.0 mm
Smallest size around copper pad 0.2 mm <0 mm
Smallest text lines not possible not possible
Silk Print - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Smallest lines 0.20 mm 0.15 mm
Smallest distance between lines 0.20 mm 0.15 mm
Minimum clearance to copper pads 0.20 mm 0.15 mm
Carbon Print - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Smallest pad-to-pad distance not possible 0.50 mm
Tolerances, Values, Marks & Norms - Flexible Printed Circuits - Prototypes to Mass Production - FPCs Online calculation/Standard on explicit enquiry
Max. offset drill centre to centre of reference 0.10 mm 0.075 mm
Max. offset solder stop (laquer or cover lay) / copper structures 0.20 mm 0.10 mm
Finished drill sizes PTH (up to 3 mm) -0.05/+0.10 mm -0/+0.10 mm
Finished drill sizes PTH (> 3 mm) -0.05/+0.10 mm -0/+0.10 mm
Finished drill sizes NPTH (up to 6 mm) -0.05/+0.10 mm -0/+0.10 mm
Finished drill sizes NPTH (>6 mm) -0.05/+0.10 mm -0/+0.10 mm
Outline +/-0.30 mm +/-0.10 mm
Max. offset outline/copper structures +/-0.30 mm +/-0.10 mm
Scoring depth not possible +/-0.20 mm
Max. offset scoring/copper structures not possible +/-0.20 mm
Etch tolerance copper thickness 5 µm not possible +0/-0.01 mm
Etch tolerance copper thickness 9 µm not possible +0/-0.01 mm
Etch tolerance copper thickness 18 µm not possible +0/-0.02 mm
Etch tolerance copper thickness 28~35 µm +0/-0.03 mm +0/-0.03 mm
Etch tolerance copper thickness 70 µm not possible +0/-0.04 mm
Material thickness tolerance +/-15% differs, please enquire
Copper thickness tolerance +/-15% +/-10%
Thickness i mmersion tin >= 0.5 µm >= 1.0 µm
Thickness tin (HAL-lead free) not possible nicht möglich
I mmersion gold for soldering purpose (nickel thickness) 1.5 µm to 3 µm 2.5 µm to 5 µm
I mmersion gold for soldering purpose (gold thickness) 0.025 µm to 0.075 µm 0.05 µm to 0.075 µm
I mmersion gold for gold-wire bonding (nickel thickness) not possible not possible
I mmersion gold for gold-wire bonding (gold thickness) not possible not possible
I mmersion gold for aluminium-wire bonding (nickel thickness) 1.5 µm to 3 µm 2.5 µm to 5 µm
I mmersion gold for aluminium-wire bonding (gold thichicht) 0.025 µm to 0.075 µm 0.05 µm to 0.075 µm
Elctrolytic soft gold for connectors, soft, bonding (nickel thickness) not possible 4 µm to 8 µm
Elctrolytic soft gold for connectors, soft, bonding (gold thickness) not possible 0.2 µm to 0.3 µm
Elctrolytic hard gold for connectors, hard, no bonding (nickel thickness) not possible 4 µm to 8 µm
Elctrolytic hard gold for connectors, hard, no bonding (gold thickness) not possible 0.8 µm to 1 µm
Solder mask thickness ca. 10 µm >15 µm
Cover lay thickness 25.4 µm from 12.5 µm
Adhesive thickness Polyimid base material to copper (epoxy) 25.4 µm from 12.5 µm
Adhesive thickness Polyimid-cover lay to copper 25.4 µm from 12.5 µm
Copper thickness inside plated holes (PTH) 5 µm to18 µm at least 6 µm at least 6 µm
Copper thickness inside plated holes (PTH) 28~35 µm at least 10 µm at least 10 µm
Copper thickness inside plated holes (PTH) 70 µm at least 12 µm at least 12 µm
Connector tolerance with siffener (total width) +/-0.15 mm +/-0.075 mm
Connector tolerance with siffener (outline to pad) +/-0.15 mm +/-0.075 mm
Chamfer angle not possible not possible
Base material RoHS-compliant yes alway yes alway
Surface finish RoHS-compliant yes alway yes alway
IPC-norm some IPC-6013 - Class 1. 2 or 3
UL-certification of FPC (UL-number, Logo, datecode) not possible possible
UL-certification of FPC base material some possible
Insert date code (WW/YY) possible, please advise in case of order/enquiry possible, please advise in case of order/enquiry
Insert supplier logo (Leiton) possible, please advise in case of order/enquiry possible, please advise in case of order/enquiry
DIN EN ISO 9001 certification for order preparation, CAM and order processing from Leiton yes yes
DIN EN ISO 9001 certification FPC supplier yes yes
DIN EN ISO 14001 certification FPC supplier no possible
DIN EN ISO 16949 certification FPC supplier no possible