Multilayer Flexible PCB Built on Polyimide With Immersion Gold and
Green Solder Mask for Wireless Intercom
(Flexible printed circuits are custom-made products, the picture
and parameters shown are just for reference)
General description
This is a type of 4 layer flexible printed circuit for the
application of Wireless Intercom at 0.2mm thick. The base laminate
is from ITEQ, It’s fabricated per IPC 6012 Class 2 using supplied
Gerber data.
Parameter and data sheet
| Size of Flexible PCB | 70.58 X 120.37mm |
| Number of Layers | 4 |
| Board Type | Flexible PCB |
| Board Thickness | 0.20mm |
| Board Material | Polyimide 25µm |
| Board Material Supplier | ITEQ |
| Tg Value of Board Material | 60℃ |
|
| PTH Cu thickness | ≥20 µm |
| Inner Iayer Cu thicknes | 35 µm |
| Surface Cu thickness | 35 µm |
| |
| Coverlay Colour | Yellow coverlay / Green solder mask |
| Number of Coverlay | 2 |
| Thickness of Coverlay | 25 µm |
| Stiffener Material | no |
| Stiffener Thickness | N/A |
| |
| Type of Silkscreen Ink | IJR-4000 MW300 |
| Supplier of Silkscreen | TAIYO |
| Color of Silkscreen | White |
| Number of Silkscreen | 1 |
|
| Peeling test of Coverlay | No peelable |
| Legend Adhesion | 3M 90℃ No peeling after Min. 3 times test |
|
| Surface Finish | Immersion Gold |
| Thickness of Nickle/Gold | Au: 0.03µm(Min.); Ni 2-4µm |
| RoHS Required | Yes |
| Famability | 94-V0 |
|
| Thermal Shock Test | Pass, -25℃±125℃, 1000 cycles. |
| Thermal Stress | Pass, 300±5℃,10 seconds, 3 cycles. No delamination, no blistering. |
| Function | 100% Pass electrical test |
| Workmanship | Compliance with IPC-A-600H & IPC-6013C Class 2 |
Features and benefits
Excellent flexibility
Reducing the volume
Weight reduction
Consistency of assembly
Increased reliability
Controllability of electrical parameter design
The end can be whole soldered
Continuity of processing
Provide small quantity, prototypes and production.
Engineering design prevents problems from occurring in
pre-production.
Applications
Touch screen, consumer card reader soft board, tablet keypad flex
board
Components of a flexible circuit
A flexible circuit consists of copper foil, dielectric substrate+
coverlay and adhesive.
Copper foil is available in two different types of copper: ED
Copper and RA copper.
ED copper is an electro-deposited (ED) copper foil produced in the
same way as the copper foil used for rigid printed circuit boards.
This also means that the copper is “treated”, i.e., it has a
slightly rough surface on one side, which ensures a better adhesion
when the copper foil is bonded to the base material.
RA copper is a rolled and annealed copper foil produced from
electrolytically deposited cathode copper, which is melted and cast
into ingots. The ingots are first hot-rolled to a certain size and
milled on all surfaces. The copper is then cold-rolled and
annealed, until the desired thickness is obtained.
Copper foil is available in thickness of 12, 18, 35 and 70 μm.
The most common available for dielectric substrate and coverlay is
polyimide films. This material can also be used as coverlay.
Polyimide is best suited for flexible circuits because of its
characteristics as stated below:
High temperature resistance allows soldering operations without
damaging the flexible circuits
Very good electrical properties
Good chemical resistance
Polyimide is available in thicknesses of 12.5, 20, 25 and 50 μm.
Base laminates for rigid printed circuit boards are copper foils
laminated together with the base materials, the adhesive coming
from the prepreg material during lamination. Contrary to this is
the flexible circuit where the lamination of the copper foil to the
film material is achieved by means of an adhesive system. It is
necessary to distinguish between two main systems of adhesive,
namely thermoplastic and thermoset adhesives. The choice is
dictated partly by the processing, and partly by the application of
the finished flexible circuit.
