A Comprehensive Analysis of PCB Boards: Functions, Manufacturing, and Future Prospects

Overview of PCB boards

PCB board, also known as printed circuit board, is an indispensable component in electronic devices. It undertakes the important tasks of connecting electronic components and transmitting signals, and is hailed as the "neural network" of electronic products. Through meticulous circuit design, the PCB board achieves electrical interconnection among components, thereby ensuring the normal operation of electronic devices. The exquisite manufacturing process and stable performance of it are directly related to the quality and service life of electronic products.

Detailed Explanation of PCB Boards

A PCB board, also known as a printed circuit board, is a type of board manufactured through a special process on an insulating substrate. It features fine structures such as conductive tracks, holes and pads, aiming to achieve electrical connections and mechanical support between electronic components. This type of board plays a crucial role in electronic devices. It not only provides stable electrical connections for components to ensure accurate signal transmission but also undertakes the task of mechanical support to guarantee the safety and stability of electronic components.

In electronic devices, PCB boards occupy an indispensable position. It can optimize the internal layout of the equipment and achieve a compact arrangement of components, thereby promoting the development of the equipment towards miniaturization and lightweight. Meanwhile, PCB boards can also enhance the performance and efficiency of circuits, providing a strong guarantee for the stable operation of electronic devices.

With the rapid development of technology, the importance of PCB boards has become increasingly prominent. In the field of communication, it undertakes complex tasks of signal transmission and processing. In the field of computers, the PCB board is the cornerstone for the collaborative work of key components such as the CPU and memory. In automotive electronics, it provides reliable circuit support for various control systems of the vehicle.

In conclusion, as the connection and support core of electronic components, the PCB board is an indispensable part of modern electronic devices. The progress and innovation of its technology will continue to drive the vigorous development of the entire electronics industry.

The early PCB board forms were relatively simple. For instance, the earliest single-sided boards had one side covered with copper foil for wiring, and components were connected by pins or soldering. Limited by the wiring space, single-panel is mainly suitable for electronic devices with single functions and simple circuits.

With the advancement of technology, double-sided panels have emerged. It features copper foil wiring on both sides, and the circuit connection between the two layers is achieved through metallized holes, which greatly enhances the flexibility of the wiring and the component capacity, adapting to more complex circuit design requirements.

However, with the increasingly rich functions of electronic devices, more stringent challenges have been posed to PCB boards. As a result, multi-layer boards gradually became the mainstream in the industry. The multi-layer board adds multiple layers of copper foil inside and connects them through carefully designed conductive through holes. This not only optimizes space utilization but also effectively reduces signal interference, further enhancing electrical performance.

Nowadays, high-density interconnect boards (HDI) have become a model of advanced technology. HDI boards adopt micro-circuit, micro-aperture and higher layer count designs, promoting the high-density and high-performance development of electronic devices. It plays a crucial role in devices such as mobile phones and laptops that pursue miniaturization and high performance.

During the development history of PCB boards, the manufacturing process has also undergone earth-shaking changes. From the initial manual production to the realization of automated production, from simple etching processes to high-precision laser drilling, the application of nanotechnology, as well as advanced lamination and surface treatment technologies, all have provided solid support for the performance improvement and quality leap of PCB boards.

Looking ahead, PCB board technology will continue to innovate and develop, striving to achieve the goals of higher precision, faster transmission speed, smaller size, lower cost and greater environmental friendliness, providing a more powerful impetus for the prosperity of the electronics industry.

(1) Cutting materials

Cutting, as the initial step in PCB manufacturing, involves cutting large sheets of copper clad laminates into appropriate sizes. In the production of single and double panels, this step will be precisely cut according to the design requirements. Although baking plates (also known as baked plates or baking boards) do not significantly change the size of the plate material, they can effectively remove internal moisture and relieve stress through baking, thereby preventing the plates from warping. In addition, the edges of the board need to be finely processed, such as planing or grinding, to ensure they are smooth and free of burrs, so as to avoid adverse effects on subsequent processes. Chamfering treatment is to change the right corners of the board to rounded corners, which is also aimed at ensuring the smooth progress of subsequent processes.

(2) Film application

The film application operation is usually carried out on a dedicated film application machine. This process involves peeling off the polyethylene protective film on the dry film and adhering the dry film resist to the copper-clad laminate under heating and pressurization conditions. When installing a new machine, it is necessary to carefully adjust the upper and lower hot press rollers to be axially parallel and gradually increase the pressure to an appropriate state. The temperature for applying the film is usually maintained at around 100℃, but it may vary depending on factors such as the type of dry film and environmental conditions. The transmission speed also affects the film application effect and is usually adjusted between 0.9 and 1.8 meters per minute, which is related to the film application temperature.

(3) Exposure

Exposure is the reaction of the photosensitive film triggered by ultraviolet rays. In the circuit exposure process, a photosensitive film is first attached to the copper-clad laminate and exposed to ultraviolet light together with the circuit graphic negative to trigger the polymerization reaction of the photosensitive film. The exposure process of solder mask is similar, but mainly it covers the area that needs to be welded to expose the solder pad. During this process, the selection of the light source is of vital importance. For instance, hammer lamps and high-pressure mercury lamps, which have high radiation intensity within the wavelength range of 310 to 440nm, are ideal choices. Meanwhile, the control of exposure time also directly affects the final effect.

(4) Etching

Etching is a key step in removing unwanted copper foil. Common etching methods include immersion, bubbling, splashing and spraying, among which spray etching has the best effect and can effectively reduce side etching. The characteristics of the etching solution, such as PH value, density and the thickness of the copper foil, will all affect the etching result. For example, the lateral etching of alkaline etching solution increases when the PH value is relatively high, so it is generally controlled below 8.5. Choosing an etching solution with a high copper concentration helps to reduce side etching. The etching of fine wires is suitable for thin copper foil.