APTPCB Rigid-Flex Manufacturing Services

From concept stackup to qualified production, we engineer rigid-flex boards that fold, hinge, and survive repeated stress without sacrificing impedance or assembly throughput.

Rigid-Flex Architectures

Choose the right rigid/flex split, layer count, and stiffener mix to balance density, bend profile, and cost.

• Type 1 Rigid-Flex – Single flex core laminated to two rigid sections for static folds and connector savings.
• Type 2 Rigid-Flex – Multiple flex layers with microvias between rigid and flex for higher routing density.
• Air-gap Rigid-Flex – Independent flex tongues between rigid islands to improve dynamic reliability.
• Bookbinder Rigid-Flex – Offset flex layers of different lengths prevent stress at the fold in high-layer builds.
• Any-Layer Rigid-Flex – Flex and rigid sections share stacked microvias for ultra-compact camera or sensor modules.

Interconnect & Bend Features

• Staggered Microvias: Layer-to-layer interconnects that avoid stacking over bend areas for better fatigue life.
• Button Plated PTH: Copper buttons reinforce vias crossing rigid-to-flex transitions.
• Back-drilled Interconnect: Removes stubs in rigid sections feeding flex tails for SerDes and RF signals.
• Selective Stiffener Vias: Dedicated vias tie ground pours to copper stiffeners for EMI control.
• Laser Skived Coverlay: Precisely opens pads and relieves adhesive around dynamic bends.
• Embedded Copper Coins: Local thermal paths in rigid sections without adding mass to flex regions.

Stackup Examples

• 8 Layer (2 Flex + 6 Rigid): Two 25 µm PI layers sandwiched between FR-4 cores for wearable compute.
• 12 Layer Bookbinder: Alternating flex tongues with offset lengths to protect 0.4 mm pitch BGAs.
• Rigid-Flex-Rigid (6R-4F-6R): High-density avionics module with low-loss rigid materials and RA copper flex tails.

Materials & Design Guidelines

Adhesiveless PI, LCP, and matched FR-4 or low-loss rigid materials keep coefficients aligned. Copper button plating, hatched grounds, and coverlay relief manage impedance without cracking.

• Match CTE between rigid and flex sections to avoid warpage during lamination.
• Use RA copper ≤ 35 µm in dynamic bends; reserve thicker copper for static sections.
• Keep plated through-holes out of bend areas and maintain 10× thickness bend radius minimum.
• Design coverlay relief with teardrops and fillets to prevent cracking at pad edges.

Reliability & Validation

Every build includes electrical test, AOI, X-ray of buried vias, and optional 100k-cycle bend testing with resistance logging to certify mechanical integrity.

Cost & Application Guidance

• Type 1 Rigid-Flex: Lowest cost when only one dynamic flex tail replaces wiring.
• Bookbinder / multilayer: Budget for additional lamination passes but consolidate rigid islands to reduce tooling.
• High-speed rigid-flex: Use low-loss rigid cores only where required to control material spend.