Single-sided Flex PCB

Single-sided flex PCB boards are the most common type of flexible circuit and can be found everywhere in ordinary electronic products.

As your flex circuit supplier, you will be able to manufacture boards with smaller trace spacing and micro vias. We also offer extremely fast rapid flex circuit prototyping services.

For flexible PCB with a simple structure, the manufacturer's capabilities are reflected in the production of ultra-fine lines, ultra-thin circuit boards, etc.

Stack-up

The stack-up of single-sided flex PCB is the simplest. The copper layer is usually a single-sided design, which is suitable for circuits that do not require double-sided connection. Through the following stackup, you will clearly understand the single-sided flex PCB structure.

Key Features of Single-Sided Flex PCBs

Only one conductive layer (copper foil)
High flexibility and ultra-thin structure
No plated through-holes (PTH) required

Stack-up of Single Sided Flexible Circuit

Flex Plus has industry-leading expertise in ultra-fine line and ultra-thin flex PCB manufacturing, offering solutions for next-generation electronic devices.

Ultra-Fine Line Processing

Minimum line width/spacing: 10μm (0.01mm)

Advanced laser direct imaging (LDI) & high-precision etching

Enables high-density interconnects (HDI) for compact devices

Ultra-Thin Flexible PCB

Base material thickness: 6μm - 12.5μm (0.25mil - 0.5mil) polyimide

Copper foil thickness: 9μm - 18μm (0.25oz - 0.5oz)

what is single sided with dual access flex pcb?

single sided flex pcb with dual access(bare back fpc)

Stack-up of Single Sided Flexible Circuit with Dual Access

A single-sided with dual-access flex PCB is a special type of single-sided flex PCB that allows access to the same copper layer from both sides of the PCB. Unlike a standard one-layer flex PCB, which has copper exposed only on one side, a dual-access design creates openings in the coverlay or polyimide substrate, enabling component connections or soldering from both sides.

Key Features

Single copper layer, but accessible from both sides
No plated through-holes (PTH) needed
Reduces weight and thickness compared to double-sided flex PCBs
Flexible & lightweight, ideal for compact devices
Lower manufacturing cost than double-sided flex PCBs

How Does Dual Access Work?

In a single-sided flex PCB, the coverlay usually insulates one side of the copper. However, in a single-sided dual access flex PCB, specific areas of the coverlay are opened on both sides, exposing the same copper layer from both the top and bottom. This allows:

Soldering components on both sides without needing vias
Conductive adhesive bonding from either side
More compact and flexible designs

Advantages Over Standard Single-Sided Flex PCB

Feature	Standard Single-sided Flex PCB	Dual Access Flex PCB
Manufacturing Cost	Lower	Slightly higher
Flexibility	High	Slightly less flexible
Copper Layers	1	1 (Accessible from both sides)
Component Placement	One side only	Both sides
Through-Hole (PTH)	Not possible	Not needed

Comparison with Double-Sided Flex PCB

Feature	Dual Access Flex PCB	Double-sided Flex PCB
Electrical Connection	No PTH needed	Requires PTH
Cost	Lower	Higher
Flexibility	Higher	Slightly less flexible
Application	Low-cost, simple designs	High-density circuits
Copper Layers	1	2

A single-sided with dual access flex PCB provides a cost-effective and flexible solution for applications requiring component mounting on both sides without needing plated through-holes. It is an ideal alternative to two-layer flex PCB when electrical connections between layers are not required.

Benefits

Low cost: Due to its single-sided design, the manufacturing cost is relatively low, suitable for cost-sensitive applications.
Light and flexible: Suitable for devices with limited space, providing high degree of freedom in design options.
Shorter production cycle: It takes less time to produce than multi-layer or double-sided flex circuit boards and enables faster delivery.
High reliability: Works well for high-frequency and high-speed uses, especially in mobile devices and medical devices.

Applications

Wearable devices: It’s light and bendy, so it’s popular for smart watches, fitness trackers, etc.
LED Screens: Perfect for making flexible LED displays.
Consumer electronics: Used in consumer electronics such as mobile phones, printer, etcs.
Medical equipment: Small medical devices like pacemakers and sensors.

Advanced Features

High frequency performance: Works great for sending signals quickly in high-frequency situations.
Save power: Its simple one layer structure uses less electricity.
Miniaturized design: Can be made ultra thin and packed with features to fit in small spaces.

Warping can occasionally occur during processing or use, especially in single-sided constructions. Learn how to address and prevent warping in single-sided FPC boards.