Parameter

Standard Capability

Advanced / Extended Capability

Notes & Standards

Total Layer Count (Rigid + Flex)

4 to 12 layers

Up to 24+ layers

Includes combination of rigid multilayer and flexible layers.

Rigid Section Material

FR-4 Standard Tg (140°C), FR-4 High Tg (170°C+)

Rogers, Polyimide, High-Speed/ Low-Loss Laminates

Various dielectric thicknesses available.

Flex Section Core Material

Polyimide (PI), Adhesiveless (2-Layer) Preferred

Adhesive-based PI, Specialized Flex Films

Adhesiveless (e.g., Kapton+Cu) is standard for high reliability in dynamic bends.

Flex Core Thickness (w/o Cu)

1 mil (25µm), 2 mil (50µm)

0.5 mil (12µm) to 4 mil (100µm)

Thinner cores for tighter bends; thicker for improved dimensional stability.

Flex Copper Weight

0.5 oz (18µm), 1 oz (35µm) RA Copper

0.33 oz (12µm) to 2 oz (70µm)

Rolled Annealed (RA) Copper standard for flex endurance.

Rigid-to-Flex Bonding

Low-Flow or No-Flow Prepreg

Multi-Step Lamination Cycles

Critical process to prevent resin seepage into flex areas and ensure integrity.

Coverlay (Flex Protection)

PI Film with Adhesive, Laser/Die-cut

Photo-Imageable Covercoat (PIC)

Standard opening tolerance: ±0.075 mm (±3 mil).

Parameter

Standard Capability

Advanced / Extended Capability

Notes & Standards

Max. Panel Size (for Processing)

24" x 24" (610mm x 610mm)

26" x 30" (660mm x 760mm)

Panel utilization depends on design geometry.

Board Outline Tolerance

±0.15 mm (±0.006")

±0.10 mm (±0.004")

Via CNC routing. Contour complexity may affect tolerance.

Min. Rigid Section Thickness

0.4 mm

0.3 mm

Depends on layer count and material.

Min. Flex Section Thickness (Single Layer)

~0.10 mm

~0.08 mm

PI + Cu + Coverlay.

Min. Bend Radius (Static Installation)

6x total flex zone thickness

4x total flex zone thickness

Critical DFM rule. Must be clearly specified in bend areas.

Min. Bend Radius (Dynamic Flex)

10x total flex zone thickness

8x total flex zone thickness

For repeated bending during product life. Requires adhesiveless construction.

Stiffeners (Local Reinforcement)

FR-4, PI, Aluminum, Stainless Steel

Custom shapes & thicknesses. PSA or Thermally Bonded.

Used under connectors or components on flex areas.

Parameter

Standard Capability

(Rigid & Flex Areas)

Advanced / Extended Capability

Notes & Standards

Min. Trace / Space (Inner Layers)

0.075 mm / 0.075 mm (3/3 mil)

0.050 mm / 0.050 mm (2/2 mil)

For 1 oz Cu. Flex areas may require larger geometry.

Min. Trace / Space (Outer Layers)

0.10 mm / 0.10 mm (4/4 mil)

0.075 mm / 0.075 mm (3/3 mil)

Etch Tolerance

±0.025 mm (±1.0 mil)

±0.015 mm (±0.6 mil)

Additive to minimum feature size.

Conductor Thickness Uniformity

≥ 80%

≥ 85%

Measured via cross-section; critical for controlled impedance.

Controlled Impedance

±10% tolerance

±7% or ±5% tolerance

Coupon-based TDR testing. Requires early stack-up collaboration.

Parameter

Standard Capability

Advanced / Extended Capability

Notes & Standards

Drilled Hole (PTH) Diameter (Min)

0.20 mm (8 mil)

0.15 mm (6 mil)

Mechanical drilling. Aspect ratio up to 10:1 in rigid areas.

Laser Microvia Diameter (Min)

0.075 mm (3 mil)

0.050 mm (2 mil)

For HDI structures in rigid sections.

Plated Hole Wall Thickness (Min)

0.020 mm (0.8 mil)

0.025 mm (1.0 mil)

Ensures reliability during thermal cycling.

Pad-to-Hole Ratio (Annular Ring)

0.10 mm (4 mil) min.

0.075 mm (3 mil) min.

Especially critical in flex areas.

Via-in-Flex (Staggered/Breakout)

Supported (non-plated)

Plated Vias in Flex (limited bend)

Requires specific design to avoid cracking. Not recommended in dynamic bend zones.

Finish Type

Typical Thickness

Applicability & Notes

ENIG

Ni: 3-5µm / Au: 0.05-0.15µm

Most common. Excellent for fine-pitch, wire bonding, and flatness.

Immersion Silver

0.1 - 0.3µm

Excellent solderability, good for high-frequency. Requires anti-tarnish.

Immersion Tin

0.8 - 1.2µm

Good solderability, cost-effective. Limited shelf life.

HASL-LF

1-40µm (variable)

Robust, cost-effective. Not recommended for fine-pitch or flex-only areas.

OSP

0.2 - 0.5µm

Low cost, flat. For simple assemblies with quick turnaround.

Electrolytic Hard Gold (Selective)

Au: 0.5µm - 2.5µm (20-100µ")

For edge connectors or high-wear contact areas on rigid sections.

ENEPIG

Ni: 3-5µm / Pd: 0.05-0.1µm / Au: 0.03-0.05µm

Superior for wire bonding and multiple reflows.

Test/Inspection Type

Standard Method

Capability / Standard

Electrical Test

Flying Probe (100% Netlist)

Fixture Test for high-volume production.

Automated Optical Inspection (AOI)

2D/3D AOI

On outer layers for opens, shorts, and defects.

X-Ray Inspection (AXI)

2D & 3D AXI

For BGA, QFN, and internal layer/ via inspection (upon request).

Microsection Analysis

IPC TM-650 2.1.1

For process qualification & failure analysis (plating, lamination).

Flex & Bend Testing

IPC TM-650 2.4.3, Customer-Specific

Dynamic cycling or one-time fold to validate design.

Thermal Stress / Shock

IPC TM-650 2.6.7, 2.6.8

Solder Float, Thermal Cycling per IPC-6013.

Controlled Impedance Test

TDR (Time Domain Reflectometry)

Coupon-based verification to specified tolerance.

Peel Strength Test

IPC TM-650 2.4.9

For adhesion of copper and coverlay.

Compliance Standard

IPC-6013 (Performance Spec for Rigid-Flex)

Designed and manufactured to meet Class 2 or Class 3 requirements.