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

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.