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HDI Rigid-Flex PCB - PCB circuit board and PCBA manufacturing

HDI Rigid-Flex PCB

In the era of 5G mmWave, foldable displays, and compact ADAS radar—where devices demand ultra-dense wiring and 3D flexibility—traditional rigid HDI boards or basic flex PCBs fall short. Our HDI Rigid-Flex PCB solves this gap by integrating High-Density Interconnect (HDI) microvia technology with rigid-flex construction, delivering the precision to support high-speed signals and the adaptability to fit complex form factors—all while cutting device size and improving reliability.

Engineered for HDI Precision & Flexible Adaptability

Every board is built to our technical specifications, with a focus on the unique needs of high-density, high-performance applications:

HDI-Optimized Materials:

Rigid regions use High-Tg FR4 (Tg≥170℃) for stable component mounting, or low-loss high-frequency laminates (dielectric constant 3.5±0.1 @10GHz) to minimize signal attenuation in 5G/mmWave systems. Flexible sections rely on adhesiveless polyimide (PI, Dk 3.4–3.6 @1MHz) for durable bending, or liquid crystal polymer (LCP, Dk 3.7±0.2 @10GHz) for ultra-high-frequency stability—critical for 25Gbps+ data transfer.

Microvia & Layer Design:

With 6–18 total layers (typical 6 rigid + 2 flexible), the PCB features laser-drilled microvias as small as 0.04mm (hole wall roughness ≤1μm)—enabling 2x more component density than standard rigid-flex boards. Rigid sections (0.6–1.4mm thick) secure chips and connectors, while thin flexible sections (0.08–0.25mm) fold or curve to fit tight spaces, eliminating bulky cables and reducing assembly complexity.

Durable Finishes for HDI Reliability:

Choose ENIG (for corrosion resistance in medical/automotive environments), Immersion Silver (for high-speed signal integrity), or OSP (for cost-effective consumer electronics). Selective hard gold plating is available for high-wear contact pads—ideal for ADAS radar connectors that need repeated mating.

Key Advantages That Define HDI Rigid-Flex Performance

Our design prioritizes the unique demands of high-density, flexible systems—setting it apart from basic rigid-flex or standard HDI:

High-Speed Signal Integrity:

Tight ±6% impedance control ensures stable transmission of 25Gbps signals (e.g., 5G mmWave, HDMI 2.1), while low-variation dielectric materials (LCP/high-frequency FR4) reduce insertion loss by up to 30% vs. conventional PI-flex boards.

Density Without Compromise:

0.04mm microvias and 0.035mm line widths/line gaps let you pack more components (e.g., sensors, ICs) into a smaller footprint—cutting device size by 40% compared to rigid HDI boards with the same functionality.

Toughness for Real-World Use:

Operates from -45℃ to +130℃, withstanding automotive underhood heat or aerospace temperature swings. Static applications (e.g., medical endoscopes) handle bending radii ≥5x the flexible layer thickness, while dynamic uses (e.g., foldable phone hinges) endure ≥10,000 cycles at ≥25x bending radius—no microvia cracking or signal drop.

Compliance You Can Trust:

Manufactured to IPC-2226A (HDI design) and IPC-6018F (rigid-flex) standards, with optional ISO 13485 (medical) and IATF 16949 (automotive) certifications. Every board undergoes 3D X-Ray inspection for microvia quality and bend testing to ensure durability.

Built for the Most Demanding High-Density Applications

Our HDI Rigid-Flex PCB is tailored to technologies where density and flexibility are non-negotiable:

  • Foldable Phones/Tables: Microvias support dense display driver and sensor wiring, while flexible sections enable 200,000+ hinge bends without failure.
  • 5G mmWave Modules: LCP or high-frequency laminates deliver low-loss signal transmission for small-cell base stations and consumer 5G devices.
  • Automotive ADAS Radar: High-temperature tolerance (-45℃~+130℃) and ±6% impedance control ensure reliable 77GHz radar performance for collision avoidance.
  • Medical Endoscopes: Compact, flexible design navigates bodily cavities, with biocompatible PI and ENIG finish to meet ISO 13485 standards.
  • Aerospace Inertial Navigation: Lightweight, vibration-resistant construction supports dense sensor arrays in satellites or drones.

Partner for Custom HDI Rigid-Flex Solutions

Whether you’re designing a 5G module, foldable device, or medical tool, we’ll optimize your HDI Rigid-Flex PCB for layer count, microvia size, and material selection—ensuring it meets your performance, space, and compliance goals. To turn your design needs into tangible solutions, connect with the IPCB technical team today: our experts offer personalized consultations, validate microvia and layer structure designs, and align material choices with your application’s unique constraints, guiding you smoothly from prototype development to mass production.

Product Specifications

AttributeSpecification
ProductHDI Rigid-Flex PCB (High-Density Interconnect Rigid-Flex Printed Circuit Board)
MaterialRigid: High-Tg FR4 (Tg≥170℃) / high-frequency laminates Flexible: Adhesiveless PI (polyimide)
Quality standardIPC-2226A
Dielectric constantRigid: 4.3–4.7 (FR4) / 3.5±0.1 (high-frequency) Flexible: 3.4–3.6 (PI) / 3.7±0.2 (LCP)
Layers6–18 total
ThicknessRigid: 0.6–1.4mm Flexible: 0.08–0.25mm Overall: 0.3–1.6mm
Copper thicknessOuter: 1/4 oz–2 oz Inner: 1/2 oz–2 oz
Surface technologyENIG, Immersion Silver, OSP; selective hard gold
Special requirementsImpedance control: ±6% Laser microvia: Min 0.04mm (roughness ≤1μm) Bending radius: ≥5x (static) / ≥25x (dynamic, >10,000 cycles) Operating temp: -45℃~+130℃
ApplicationFoldable phones, 5G mmWave modules, automotive ADAS radar, medical endoscopes, aerospace inertial navigation

iPCB Circuit provides support for PCB design, PCB technology, and PCBA assembly. You can request technical consultation or quotation for PCB and PCBA here, please contact email: pcb@frankenthalerfoundation.org

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