Flexible PCB Materials and Manufacturing Tolerances
This is the technical reference for flexible-circuit materials, copper constructions, stiffeners, surface finishes, drilling and manufacturing tolerances.
Final capability depends on the complete flex stack-up, copper thickness, coverlay system, bend requirements, hole structure and panel design, so designs that approach the listed limits should be reviewed before release.
Flex PCB Capabilities
Material selection, process tolerances, manufacturing logistics, and your flex supplier all play an important role in producing a cost-effective and reliable flex circuit design.
PCB Company will assist you in designing for manufacturing to minimise overall program costs. Listed are standard materials and capabilities. Come speak with us should your design require tighter tolerances or special process treatments.
| Material Selection | |
| Polyimide Thickness | 0.0005″ (12 um), 0.001″ (25 um), 0.002″ |
| (50 um), 0.003″ (75 um), 0.005″ (125 um) | |
| Copper (thickness) | 0.25 oz.(9 um), 0.33 oz.(12 um), 0.5 oz. (17 um), 1 oz.(35 um), 2 oz.(70 um) |
| Copper Foils | Polyimide, Polyester, LPI (liquid photo imageable), PIC(photo imageable cover coat) |
| (rolled-annealed) | |
| Stiffeners | FR-4, Polyimide, Metal, or customer-supplied |
| Thermo-bond Adhesives | Acrylic, Phenolic Butyral, Modified Epoxy |
| Surface Finishes | Solder (hot air levelling or tin/lead plating), Electrolytic Soft Bondable Gold, Hard Gold, ENIG (electroless nickel immersion gold), Entek 106A, & Immersion Tin |
| Process Capabilities and Tolerances | |
| Minimum Trace/Space | 0.0015″/.002″ (0.33 oz.) |
| 0.002″/.0025″ (0.5 oz.) | |
| 0.003″/.0035″ (1 oz.) | |
| Minimum Via Hole Diameter (before plating) | 0.006″ (NC Drill) |
| 0.002″ (UV Laser) | |
| Minimum Blind Via Diameter (before plating) | 0.004″ (UV Laser) |
| Trace to Edge Distance | 0.010″ ( NC Route ) |
| 0.008″ (Die Punch) | |
| 0.001″ (UV Laser)* | |
| Trace to Edge Tolerance | 0.005″ ( NC Route ) |
| 0.003″ (Die Punch) | |
| 0.001″ (UV Laser) | |
| Cover Layer Aperture Positional Tolerance | 0.005″ (Cover Film) |
| 0.002″ (LPI and PIC) | |
| 0.001″ (Laser Ablation)** | |
*Trace to edge distance should be greater than 0.003″ for proper copper insulation
** Laser-defined apertures created by ablating cover layer material