Printed Circuit Board (PCB) Industry Overview

printed circuit boards (PCBs) are critical supporting components in electronic devices, with a wide range of industry-standard names, including ceramic circuit boards, alumina ceramic circuit boards, aluminum nitride ceramic circuit boards, PCBs, aluminum substrates, high-frequency boards, thick copper boards, impedance boards, ultra-thin circuit boards, and printed (copper etching) circuit boards.

PCBs miniaturize and visualize circuits, playing an irreplaceable role in the mass production of fixed circuits and the optimization of electrical layouts. Flexible Printed Circuits (FPCs), made from polyimide or polyester film, feature high reliability, high wiring density, light weight, thin thickness, and excellent flexing performance.

The development of FPCs and PCBs has spawned rigid-flex boards (FPCB). Rigid-flex boards are fabricated by laminating flexible and rigid circuits through specialized processes, integrating the properties of both FPCs and PCBs.

Classification of Circuit Boards

By Layer Count

1. Single-sided PCBs

The most basic type, with components on one side and conductors on the other. They are simple to manufacture and low-cost, but unsuitable for complex electronic products.

2. Double-sided PCBs

An upgraded version of single-sided boards, with copper traces on both sides connected by plated through-holes to form required circuit networks.

3. Multilayer PCBs

Consist of three or more conductive pattern layers laminated with insulating materials. They represent the trend of electronic information technology toward high speed, multi-function, large capacity, miniaturization, and light weight.

By Material Flexibility

• Rigid PCBs (PCB)

• Flexible PCBs (FPC)

• Rigid-Flex PCBs (FPCB)

Domestic Technical Status of PCB Testing

Domestic research on PCB automatic inspection systems began in the early to mid-1990s, with a late start and limited research institutions involved. PCB defect automatic optical inspection (AOI) technology remains at a relatively preliminary level.

Due to the high cost of foreign automatic inspection equipment and the lack of mature domestic PCB automatic testing machines, most domestic PCB manufacturers still rely on manual inspection using magnifiers or projectors. Manual inspection causes high labor intensity, eye fatigue, and a high miss rate. Moreover, it cannot meet the inspection requirements of high-density, high-precision PCBs (0.10–0.12 mm line width/space).

Constrained by outdated testing methods, the qualified rate of domestic 8–12 layer multilayer PCBs is only 50%–60%, which has become a major bottleneck restricting industry development.