Double-sided Flex PCB

Double-sided flexible PCB is an advanced solution for modern electronic design, combining flexibility with functionality. Unlike single-sided flex PCB and a dual access flex PCB, it has conductive traces on both sides of the flexible substrate, this type of printed circuit board allows for complex circuit design in a compact space, making it an excellent choice for advanced and space-saving applications. Ideal for applications that require dynamic movement or constrained layouts.

Stack-up

Double-sided flex PCBs usually include two layers of copper circuits, based on polyimide or other flexible substrates, and the two copper layers are wired separately and connected by punching. This design provides more wiring space and more complex circuit design capabilities than single-sided circuit boards.

Stack-up of Double Sided Flexible PCB board

When it comes to manufacturing 2 layers flex PCB, there is a wide range of material options available, including PI, PET, PEN, LCP, and more. Depending on your specific application needs, we can help you explore which materials are the best fit. Additionally, we offer various copper thicknesses to ensure your requirements are fully met.

For stiffeners in double-sided flexible PCBs, you can select from materials such as polyimide, FR-4, steel sheets, aluminum sheets, and others to suit your design and performance goals.

Here are the commonly used materials along with their standard thicknesses:

Substrate (Base Material)

Material: Polyimide (PI), Polyester (PET), PEN, PTFE

Standard Thickness: 12.5µm (0.5mil), 25µm (1mil), 50µm (2mil)

Conductive Layer (Copper Foil)

Material: Rolled Annealed (RA) Copper, Electro-Deposited (ED) Copper

Standard Thickness: 12µm (1/3oz), 18µm (1/2oz), 35µm (1oz), 70µm (2oz)

Adhesive Layer (For Bonding Layers)

Material: Acrylic, Epoxy, Modified Epoxy, Polyimide Adhesive

Standard Thickness: 12.5µm (0.5mil), 25µm (1mil), 50µm (2mil)

Coverlay (Insulation Protection)

Material: Polyimide Film + Adhesive

Standard Thickness: 25µm (1mil) PI + 12.5µm (0.5mil) Adhesive, 50µm (2mil) PI + 25µm (1mil) Adhesive

Stiffener (For Mechanical Support)

Material: Polyimide, FR4, Stainless Steel, Aluminum

Standard Thickness: 0.1mm (4mil), 0.2mm (8mil), 0.3mm (12mil), 0.5mm (20mil), 1.0mm (40mil)

Solder Mask / Covercoat (Optional)

Material: Polyimide-based Liquid Photoimageable (LPI), Epoxy-based LPI

Standard Thickness: 10–15µm

Benefits

Higher design flexibility: Double-sided design provides more wiring layers, which can support more complex circuit designs.
Higher density: More circuit connections can be achieved in a smaller space, suitable for high-density applications.
Improved electrical performance: Through double-sided wiring, signal interference can be reduced and signal stability and reliability can be improved.
Suitable for medium and high-cost applications: Slightly more expensive than single-sided circuit boards, but suitable for applications that require higher performance and complex circuits.

Applications

Portable devices: Smart phones, tablets, notebooks, etc., small devices that require more complex circuit designs.
Automotive electronics: Such as automotive electronic control systems, LED display controllers, etc.
Medical equipment: Double-sided flex PCBs are ideal for sensors, battery management systems, etc.
Industrial equipment: Suitable for complex circuit designs in robot control systems and automation equipment.

Advanced Features

High-density interconnect (HDI): Double-sided design can support more components and higher-density lines.
Low-noise design: Through precise layout, signal interference and noise problems are reduced, and the overall performance of the circuit board is improved.
Automated production: Supports precision laser cutting and punching technology to further improve manufacturing accuracy.