Click the above “Mechanical and Electronic Engineering Technology” to follow usPrinted circuit boards can be classified in various ways. Based on the number of conductive layers, they can be divided into single-sided boards, double-sided boards, multi-layer boards, and new multi-layer boards; based on the material of the board, they can be classified into rigid boards, flexible boards, and rigid-flex boards; based on product structure, they can be categorized into thick copper boards, high-frequency boards, high-speed boards, metal base boards, and other structural types of printed circuit boards.
Single-Sided BoardA single-sided board is the most basic type of printed circuit board, with components concentrated on one side and wires on the other. Since wires only appear on one side, it is called a single-sided board, mainly used in earlier circuits and simple electronic products.Double-Sided BoardA double-sided board is a printed circuit board with conductive patterns printed on both sides of a double-sided copper-clad board. Since both sides have conductive patterns, metalized holes are generally used to connect the conductive patterns on both sides. This type of PCB can route wiring to the other side through metal holes, allowing for more complex circuits.Multi-Layer BoardA multi-layer board is a printed circuit board with three or more layers of conductive patterns. The inner layers are formed by stacking conductive patterns with insulating semi-cured sheets, while the outer layers are made of copper foil, pressed into a single unit. To connect the printed wires sandwiched between the insulating substrates, the vias on multi-layer boards need to be processed through metalized holes to connect with the printed wires in the insulating substrates. The production of conductive patterns on multi-layer boards primarily uses photolithography, and the number of layers is usually even, including the two outermost layers.
New Multi-Layer BoardWith the increasing trend of miniaturization in electronic products, multi-layer boards are also gradually evolving towards higher layers, higher precision, and higher density, resulting in various special new multi-layer boards such as HDI boards and IC packaging substrates. HDI boards, short for High Density Interconnect printed circuit boards, are also known as micro-hole boards or stacked boards. HDI is a type of printed circuit board technology that enables high-density wiring, commonly used to create high-precision circuit boards. HDI boards are generally manufactured using a stacking method and employ laser drilling technology to create conductive vias, resulting in inter-layer connections primarily through buried and blind vias. Compared to traditional multi-layer printed boards, HDI boards can achieve characteristics such as high-density, fine wiring, and small aperture sizes. HDI boards are mainly used in fields with high-density requirements, such as consumer electronics, automotive electronics, and more, including smartphones, laptops, and autonomous driving sensors, with smartphones being the largest application area for HDI boards. Currently, communication products, network products, server products, automotive products, and even aerospace products utilize HDI technology. Packaging substrates refer to IC (Integrated Circuit) packaging boards, which are directly used to carry chips, providing electrical connections, protection, support, heat dissipation, and assembly functions to achieve multi-pin configurations, reducing the size of packaging products, improving electrical performance and thermal efficiency, and achieving ultra-high density or multi-chip modularization. Packaging substrates involve interdisciplinary technology, incorporating knowledge from electronics, physics, and chemistry. Packaging substrates are used for semiconductor chip packaging, and storage chips for memory, micro-electromechanical systems for sensing, radio frequency modules for RFID, processor chips, and other devices all require packaging substrates.Rigid BoardA rigid board is made from a rigid substrate that is not easily bent and has a certain degree of toughness, providing support for the electronic components attached to it. Rigid substrates include fiberglass cloth substrates, paper substrates, composite substrates, ceramic substrates, metal substrates, and thermoplastic substrates. Rigid boards are widely used in computers and network equipment, communication devices, industrial control, consumer electronics, and automotive electronics.
Flexible BoardA flexible board refers to a printed circuit board made from flexible insulating substrates. Flexible boards can be freely bent, rolled, and folded, allowing for arbitrary arrangement according to spatial layout requirements, and can move and stretch in three-dimensional space, achieving integration of component assembly and wire connections. Flexible boards are widely used in smartphones, laptops, tablets, and other portable electronic devices.Rigid-Flex BoardA rigid-flex board refers to a printed circuit board that contains one or more rigid areas and flexible areas on a single board, combining the thin-layer flexible printed circuit board base and the rigid printed circuit board base through lamination. The advantage of a rigid-flex board is that it can provide the support of a rigid board while also having the bending characteristics of a flexible board, meeting three-dimensional assembly requirements. Rigid-flex boards are widely used in advanced medical electronic devices, portable cameras, and foldable computer devices.
Thick Copper BoardA thick copper board refers to any printed circuit board with a copper thickness of 3oz or more. Thick copper boards can carry large currents and high voltages while having good heat dissipation properties. Due to the thicker copper lines, thick copper boards have high requirements for bonding agents, drilling, and electroplating processes. They are widely used in industrial power supplies, medical device power supplies, military power supplies, and engine equipment.High-Frequency BoardHigh-frequency boards (High-frequency PCBs) can also be referred to as high-frequency communication circuit boards, RF circuit boards, etc. They are printed circuit boards made from special low dielectric constant and low loss materials, capable of operating at higher electromagnetic frequencies. High-frequency boards have high requirements for signal integrity and are more challenging to process, specifically in terms of pattern precision, layer alignment, and impedance control, resulting in higher costs. High-frequency boards are mainly used in communication base stations, microwave communications, satellite communications, and radar.High-Speed BoardHigh-speed boards are printed circuit boards made from low-loss high-speed materials, primarily responsible for data transmission, processing, and calculation of high-speed circuit signals between chipsets and between chipsets and peripherals to achieve chip computation and signal processing functions. High-speed boards have high requirements for fine line processing, characteristic impedance control, and insertion loss control. They are mainly used in communications, servers, memory, switches, and other fields.
Metal Base BoardA metal base board is a composite printed circuit board consisting of a metal substrate, an insulating dielectric layer, and a circuit layer. Metal base boards have good heat dissipation and mechanical processing performance, primarily applied in electronic systems with high heat generation, such as LED LCD displays, LED lighting, and automotive lights.Other Product StructuresBesides thick copper boards, high-frequency boards, high-speed boards, and metal base boards, there are other product structures of printed circuit boards such as carbon film printed boards and surface mount printed boards.
