Double Sided Flexible Circuits

Double Sided Flexible Circuits & Circuitries

Double-sided flexible circuit board consists of double-sided flexible copper clad material with coverlay opening on one or two sides. There were two conductive trace layers (normally copper) with an insulating layer (normally Polyimide) in the middle, and two conductor layers were electronically connected via plated through holes (PTH). Sometimes, there’s no PTH in the double-layer flexible circuit, as the design purpose of the bottom trace is to support the rigidness of the circuit, impedance controlled, or another special purpose.


The coverlay was made of Polyimide and already pre-cut before being laminated to copper trace so that the trace PAD and gold fingers can be accessed from both sides through the coverlay or solder mask opening. Flexible Oil also can be used as coverlay or solder mask to protect traces from oxidation and soldering.

2 Layer flex circuits allow for more complicated circuit designs than a single-sided FPC and a dual access FPC, increase the wiring density per unit area, and further space savings are realized by mounting components on both sides.

All stiffener, adhesive tape, EMI shield material and other materials can be placed on anywhere of the double layers circuits.  

Double Sided Flexible Circuits & Circuitries

Double Sided Flexible Circuits & Circuitries


Double Sided Flexible Circuit Stack Up / Structure

As double sided FPC is the most popular type of flexible circuit, so there’re various combination of different material. There’re five basic layers, from top to bottom (didn’t list the adhesive between):


  1. Coverlay (top)
  2. Copper trace (top)
  3. Polyimide: between two copper trace
  4. Copper trace (bottom)
  5. Coverlay (bottom)

Here is the most popular stack up /layer up of double layer flexible circuits:
Here is the most popular stack up /layer up of double layer flexible circuits 
Adhesiveless laminate also available and in fact, it’s very popular, as engineer want thinner thickness, bigger bend radius, chemical and high temperature, low outgassing, dimensional stability, more flexibility, longer life cycles, and impedance control and so on.


Double Sided Flex Printed Circuit Board Samples

Here are pictures of double sided flexible circuit produced by us.


Double-side Flexible Circuit  Board Custom Printed Supplier-Best FPC Two-side Flex PCB Manufacturing Original Factory-Best PFC

Click to see more photos of double-sided flexible printed circuit. manufactured by Best Technology in China, to see how it can be used in various application.


Capability of Double Side Flexible Circuit:

Copper thickness: 1/3OZ, 1/2OZ, 1OZ, 2OZ, 3OZ, 4OZ
Polymide thickness (in base material): 1/2mil, 1mil, 2mil, 3mil, 4mil
Board thickness: 0.10mm ~ 0.44mm
Maximum Dimension: 220*1,500mm
Min PTH: 0.10mm
Min LW/LS: 2mil/2mil (0.5OZ)
Impedance control: Most popular values are 50 ohm, 90 ohm, 100 ohm, other values also available




Manufacturing Process of Double-Sided Flex Circuit

Here is a simple manufacturing process of double-sided flex circuits, welcome to visit Best Technology factory in China, to see the real manufacturing process of flex circuit, then you will know better how to make 2 layers flex circuit, to see how Best Technology transfer your circuit board layout into real flex circuit.


Manufacturing Process of Double-Sided Flex Circuit 

Please contact Best Technology today for more information or any inquiry for double-sided flexible circuit board.

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