Double Layer Flexible Circuit Board (FPC) Built on Polyimide With Black Coverlay for Medium Access Control
(Flexible printed circuits are custom-made products, the picture and parameters shown are just for reference)
General description
This is a type of double sided flexible printed circuit (FPC) built on polyimide for the application of Medium Access Control.
Basic specifications
Base material: Polyimide 25μm
Layer count: 2 layers
Type: Individual FPC
Format: 156mm x 41mm = 1 type = 1 piece
Surface finish: Immersion gold
Copper weight: Outer layer 35 μm/ Inner layer 0 μm
Solder mask / Legend: Black coverlay / white
Final PCB height: 0.25 mm (inclusive of stiffener)
Standard: IPC 6012 Class 2
Packing: 100 pieces are packed for shipment.
Lead time: 10 working days
Shelf life: 6 months
Features and benefits
Reducing the volume;
Weight reduction;
Consistency of assembly;
Experienced sales persons and skilled customer services;
No minimum order quantity and low cost sample;
Focus on low to medium volume production;
On-time service;
More than 18 years of PCB experience;
Applications
Industrial control audio equipment, Tablet PC camera soft board, Automobile sensor flex board, LED display soft board, Tablet PC module soft board, mobile phone module flex board
General Properties of Coverlay
| Test Item | Treatment Condition | Unit | Property Date |
| IPC Standard * value | Typical Value |
| SF305C 0205 | SF305C 0309 |
| Resin Flow | A | mm | - | ＜0.15 | ＜0.15 |
| Peeling Strength (90º) ¹ | A | N/mm | ≥0.7 | 0.82 | 1.06 |
| 288℃, 5s | ≥0.53 | 0.80 | 1.11 |
| Thermal Stress ¹ | 288℃, 20s | - | - | No delamination | No delamination |
| Dimensional Stability | MD | After peeling off the paper | % | ±0.2 | ±0.1 | ±0.1 |
| TD | ±0.1 | ±0.1 |
| Chemical Resistance | After Chemical Exposure | % | ≥80 | ＞90 | ＞90 |
| Volume Resistvitiy | C-96/35/90 | MΩ-cm | ≥10^6 | 7.8 x 10^6 | 2.2 x 10^7 |
| Surface Resistance | C-96/35/90 | MΩ | ≥10^4 | 2.5 x 10^5 | 4.2 x 10^5 |
Clarifications of FPC
According to the combination of base material and copper foil, flexible circuit board can be divided into two types: flexible board with adhesive and flexible board without adhesive. The price of non-adhesive flexible PCB is much higher than that of adhesive flexible PCB, but its flexibility, bonding force between copper foil and substrate and flatness of solder are also better than that of adhesive flexible PCB. So it is only used in the high demand situations, such as the: COF (CHIP ON FLEX, flexible board with bare chip, the high flatness of the pad) and so on. Because its price is high, most of the flexible PCBs used in the market are still adhesive flexible circuit board. Because the flexible circuit board is mainly used in the situation where bending is required, if the design or process is not reasonable, it is easy to produce micro-cracks, welding and other defects.
Economy of using FPC
If the circuit design is relatively simple, the total volume is small, and the space is suitable, the traditional internal connection is much cheaper. Flexible circuits are a good design option if the circuit is complex, processes many signals or has special electrical or mechanical requirements. When the size and performance of applications exceed the capacity of rigid circuits, flexible assembly is the most economical. A 12mil pad with a 5mil through hole and a flexible circuit with 3mil lines and spacing can be fabricated on a thin film. Therefore, it is more reliable to mount the chip directly on the film. There is no flame retardant that could be an ion source. These films may be protective and solidified at higher temperatures to obtain higher glass transition temperatures. Flexible materials are less costly than rigid materials because they are free of connectors.
