Flexible Printed Circuit Board Applications (1)

1. Introduction of FLEXIBLE PRINTED CIRCUIT

The printed circuit board made of all-flexible substrates can be used for 3D three-dimensional assembly and dynamic deflection.

2. Basic materials

2.1. Copper foil substrate COPPER CLAD LAMINATE

The combination of copper foil+glue+substrate and non-sticky substrate, ie, copper foil+substrate, has a higher price and is currently used less unless there is a special need.

2.1.1. Copper Foil Copper Foil

The material is divided into ROLLED ANNEAL Copper Foil and ELECTRO DEPOSITED Copper Foil. In terms of characteristics, the mechanical properties of the rolled copper are better. When the bending property is required, most of the rolling copper thickness is selected. The 1 oz (0.7mil) 1oz 2oz is generally used in 1 oz.

2.1.2. Substrate Substrate

In the material is divided into PI (Polymide) Film and PET (Polyester) Pilm two kinds of PI higher prices but its better flame resistance PET price is lower but not heat-resistant, so if there is a need for welding most of the material thickness of PI On the other hand, it is classified as 1mil 2mil.

2.1.3. Adhesive Adhesive

Acrylic and Expoxy are the two most commonly used adhesives. Expoxy is the most commonly used adhesive. Thickness from 0.4 to 1mil is generally used 1mil thick.

2.2. Coverlay Coverlay

The cover film is composed of a base material and a glue. The base material is also divided into two materials of PI and PET. The cover film of the material is also used. The glue of the cover film is also the same as the thickness of the copper foil material. ~1.4mil.

2.3. Stiffener reinforcing material

Local areas on the flexible plate are pressed together to harden the material in order to weld the part or add reinforcement for mounting.

2.3.1. Reinforcement film is divided into two materials of PI and PET 2.3.2. FR4 is Expoxy material

2.3.3. Resin plate is generally called urea plate

The reinforcing material is generally laminated with a pressure-sensitive adhesive PRESSURE SENSITIVE ADHESIVE and a soft board, but the PI-reinforced films are all laminated using a thermosetting adhesive.

2.4. Printing ink

Printing inks are generally classified into Solder Mask inks (Legen white black) Silver inks (Silver Ink silver) and ink types UV curing (UV Curing) and Thermal baking (Thermal) Post Cure) Two species.

2.5. Surface Treatment

2.5.1. Anti-rust treatment on bare copper surface antioxidants

2.5.2. The cerium lead is printed on the bare copper surface with a paste printing method and then reflow furnace

2.5.3. Electroplating Tin/Lead (Sn/Pb) Nickel/Gold (Ni/Au)

2.5.4. Chemical deposition of tin/lead nickel/gold surface treatment by chemical liquid deposition

2.6. Adhesive (double-sided adhesive)

Colloids generally include Acrylic and Silicone adhesives, while double-sided adhesives are divided into substrate adhesives and non-substrate adhesives.

3. Commonly used units

3.1. mil: Measuring unit for line width/distance

1mil= 10-3 inch= 25.4x10-3 mm= 0.0254 mm

3.2. : Measurement unit of plating thickness

=10-6 inch

(to be continued)