With the development of science and technology, the use of FPC is becoming more and more extensive, which means to compete with PCB. However, many friends still don't know what FPC FPC is and what its features are. Let's talk about this in detail.

1、 Introduction

FPC: Flexible Printed Circuit in English, which means flexible printed circuit board in Chinese, short for flexible board.

It is to make conductor circuit graphics by using optical imaging graphics transfer and etching technology on a flexible substrate surface. The surface and inner layers of double-sided and multi-layer circuit boards are electrically connected through metallized holes. The surface of circuit graphics is protected and insulated with PI and adhesive layer.

It is mainly divided into single panel, hollow panel, double-sided panel, multi-layer panel, soft and hard combination panel.

2、 Development trend

The softboard industry first rose in Japan in about 2002. The softboard industry outside Japan began to sprout in 2003, expanded rapidly in 2005, and declined in 2006. The softboard industry fell to the bottom in mid-2007, and began to recover in 2008.

In 2005, the soft board industry has low threshold and high profit, attracting a large number of enterprises to enter.

In 2006, the competition has become increasingly fierce, and the phenomenon of oversupply is very serious. Many enterprises have to reduce prices again and again in order to survive, or even operate at a loss. At the same time, downstream customers of the softboard industry, such as large EMS manufacturers, added softboard departments and no longer outsourced softboard business, which made the softboard industry worse.

2007 was a year of ups and downs in the softboard industry. First of all, the profit fell sharply. The net profit of M-FLEX, a large softboard manufacturer, was only US $3 million in fiscal year 2007, while the net profit in fiscal year 2006 was US $40.4 million, and the net profit fell by 93%. Jiatong Technology, which is listed in Hong Kong, lost US $29.8 million in fiscal year 2007, while its profit in fiscal year 2006 was US $12.4 million.

The second is the decline in sales. Jialianyi, the largest softboard factory in Taiwan, had sales of NT $7.79 billion in 2004, and then fell for three consecutive years, with sales of NT $6.541 billion in 2007. Thirdly, the gross profit rate fell. The gross profit rate of Jialianyi was 29% in 2004, and dropped to 12% in 2007. Young Poong, the largest softboard company in South Korea, divested the softboard business from the listed company to avoid the investors' face being too ugly. If the big factory is still like this, the small factory will close down directly.

The massive closure of small factories has brought opportunities to the softboard industry, which has been recovering since the beginning of 2008. However, the softboard industry is facing a new problem, which is the economic downturn. At the beginning of 2008, the global economy experienced a downward trend, with high oil prices, the sub-prime crisis, and food prices soaring. The global economy has entered a downward path, especially in emerging countries.

The decline in demand for softboard is due to consumer electronics. When the economy is in the decline channel, the first hit is the demand for consumer electronics products with non-rigid demand, including mobile phones, laptops, flat panel televisions, LCD monitors, digital cameras, DVs and other products.

3、 Features

1. Small size and light weight. It can be used in the application of precision small electronic equipment;

2. It can be bent and flexed. It can be used to install any geometric shape equipment body;

3. In addition to static deflection, it can also be flexed dynamically. It can be used for connection between dynamic electronic components;

4. It can expand to three-dimensional space, improve the freedom of circuit design and mechanical structure design, and give full play to the function of printed circuit board;

5. Except for ordinary circuit board, flexible board. It can also have many functions, such as induction coil, electromagnetic shielding, touch switch button, etc.

4、 Main raw materials

Its main raw materials are: 1. base material, 2. covering film, 3. reinforcement, 4. other auxiliary materials.

1. Base material

1.1 Adhesive base material

The adhesive base material mainly consists of three parts: copper foil, adhesive, and PI. There are two types of single-sided base material and double-sided base material. The material with only one side of copper foil is single-sided base material, and the material with two sides of copper foil is double-sided base material.

1.2 Adhesive free substrate

The non-adhesive base material is the base material without adhesive layer. Compared with the common adhesive base material, the non-adhesive base material is composed of copper foil and PI. It has thinner, better dimensional stability, higher heat resistance, higher bending resistance, better chemical resistance and other advantages than the adhesive base material. Now it has been widely used.

Copper foil: At present, the thickness of common copper foil has the following specifications: 1OZ, 1/2OZ, 1/3OZ. Now, the thinner copper foil with the thickness of 1/4OZ has been introduced, but at present, this material has been used in China, and the ultra-fine path (line width and line spacing are 0.05MM and below) products are being made. With the increasing requirements of customers, materials of this specification will be widely used in the future.

2. Covering film

It is mainly composed of three parts: release paper, adhesive and PI. The only two parts that remain on the product are adhesive and PI. The release paper will be torn off during the production process and will not be used again (its function is to protect foreign matters on the adhesive).

3. Reinforcement

It is a special material for FPC, and is used at a specific part of the product to increase the support strength and make up for the "soft" characteristics of FPC.

At present, the commonly used reinforcement materials are as follows:

1) FR4 reinforcement: mainly composed of glass fiber cloth and epoxy resin adhesive, the same as FR4 material used for PCB;

2) Steel sheet reinforcement: the component is steel, with strong hardness and support strength;

3) PI reinforcement: the same as the covering film, it is composed of PI and adhesive release paper, but its PI layer is thicker, and it can be produced from 2 MIL to 9 MIL.

4. Other auxiliary materials

1) Pure adhesive: This adhesive film is a kind of heat-curing acrylate adhesive film, which is composed of protective paper/release film and a layer of adhesive. It is mainly used for laminating plates, soft and hard bonding plates, and FR-4/steel sheet reinforcing plates to play a bonding role.

2) Electromagnetic protective film: it is pasted on the board to play a shielding role.

3) Pure copper foil: only composed of copper foil, mainly used for hollow board production.

5、 Type

There are six types of FPC:

A. Single panel: only one side has lines.

B. Double-sided board: there are lines on both sides.

C. Hollow board: also known as window board (finger face opening).

D. Layered board: two lines (separate).

E. Multi-layer board: more than two layers of circuit.

F. Soft-hard combination board: a product that combines soft board and hard board.