Ultimate Guide to Rigid-Flex PCB Manufacturing

Producing rigid-flex PCBs is a complex, multi-step process that requires precision, advanced technology, and strict quality control. As a lead ing rigid-flex PCB manufacturer, JHYPCB employs state-of-the-art equipment and over 14 years of expertise to deliver boards that meet the stringent demands of industries like medical, aerospace, and automotive. The rigid-flex PCB manufacturing steps involve combining flexible and rigid layers into a single, reliable board. Below, we outline the 10 critical steps in JHYPCB’s rigid-flex PCB fabrication process, showcasing our commitment to quality and innovation.

Step 1. Material Preparation

The process begins with cutting high-quality materials to the required panel size. Flexible copper-clad laminates (FCCL), such as DuPont Pyralux, are used for the flex core, while FR4 is selected for rigid layers. Prepreg (glass-reinforced dielectric) and coverlays are also prepared. For rigid sections covering flex areas, copper foil is selectively removed to ensure bendability. JHYPCB’s precise material preparation ensures compatibility and durability in the final board.

Step 2. Drilling

Drilling creates vias and microvias for electrical connectivity between layers. JHYPCB uses mechanical drilling for standard through-holes and laser drilling for high-density interconnect (HDI) microvias, achieving apertures as small as 0.1 mm. Our advanced drilling systems minimize burrs and debris, ensuring clean, reliable vias critical for complex rigid-flex PCB designs.

Step 3. Circuit Generation

Circuit patterns are transferred onto the flex and rigid layers using photolithography. A dry film is applied, exposed to UV light, and developed to create the desired pattern. Acid etching then removes excess copper, leaving precise traces. For multi-layer flex cores (1–6 layers), JHYPCB laminates polyimide and rolled annealed copper, ensuring trace widths as fine as 30 µm for high-precision applications.

Step 4. Coverlay Lamination

A coverlay, typically polyimide-based, is applied to the flex core to protect the copper surface and enhance folding resistance. JHYPCB uses automated lamination systems to apply coverlays under controlled temperature and pressure, followed by automatic optical inspection (AOI) to detect any defects. This step ensures the flex sections remain durable in dynamic applications.

Step 5. Rigid Layer Lamination

Rigid FR4 layers are bonded to the flex core using prepreg under high temperature and pressure. JHYPCB’s advanced CCD hot melt equipment and automated laminating systems ensure precise alignment and strong adhesion. This step creates the hybrid structure, combining flexibility with mechanical stability, a hallmark of rigid-flex PCB fabrication.

Step 6. Black Hole Process

To enable electrical conductivity, JHYPCB applies a conductive carbon layer to via walls using the black hole method. This process metallizes the holes, preparing them for copper plating. Our proprietary approach ensures uniform carbon deposition, enhancing reliability across layers.

Step 7. Copper Plating

Vias are plated with a standard copper thickness (e.g., 1/3 oz to 3 oz for flex sections) to establish electrical connections between layers. JHYPCB’s controlled plating process ensures consistent thickness and signal integrity, critical for high-performance rigid-flex PCBs.

Step 8. Surface Finishing

A solder mask is applied to protect the board, followed by surface finishes like Electroless Nickel Immersion Gold (ENIG) or Hot Air Solder Leveling (HASL) to ensure solderability and prevent copper oxidation. Silkscreening adds labeling for assembly and traceability. JHYPCB’s rigorous AOI checks verify the integrity of this step.

Step 9. Opening Process

To create flexible sections, specific areas are removed using:

• UV Laser Depth Control: Precisely opens thin coverlays or core boards, achieving clean cuts with minimal thermal impact.
• Mechanical Routing: Forms closed paths for thicker openings, ensuring structural integrity.
• Mechanical Depth Control: Removes outer covers of thick sections for robust flex areas.

JHYPCB’s UV laser cutting technology enables rapid, precise openings, enhancing delivery times.

Step 10. Testing

Quality assurance is paramount. JHYPCB conducts:

• Automatic Optical Inspection (AOI): Detects circuit defects with high accuracy.
• Power-On Self-Tests: Verifies electrical functionality.
• Four-Terminal Sensing: Ensures minimal resistance tolerances for aerospace, medical, and automotive applications.

Our ISO9001-certified processes guarantee defect-free boards that meet industry standards.

As a trusted rigid-flex PCB manufacturer, JHYPCB’s advanced technologies, like LDI and UV cutting, ensure every step delivers precision and reliability. Curious about our capabilities? Explore our technical specifications or contact us for a free quote!