Keywords: Printed Circuit Board Manufacturer, PCB Manufacturer, PCB Manufacturing

Even though PCBs are the foundation of almost all electrical circuits today, they are frequently taken for granted. Despite this, technology in this field of electronics is developing. To account for the increased connection needed, track sizes are getting smaller, boards are getting more layers, and design standards are getting better. These changes make it possible to handle smaller SMT devices and support the production soldering procedures.

There are several methods and variations for completing the PCB manufacturing process. The primary steps in the PCB manufacturing process are the same despite the numerous minor differences.

PCB constituents

Many different materials may be used to create printed circuit boards or PCBs. The most popular is found in FR4, a type of glass fiber-based board. This offers a respectable level of stability with temperature fluctuation, does not degrade much, and is not too costly. For the PCBs in low-cost commercial goods, there are other less expensive materials available. PTFE-based printed circuit boards can be utilized for high-performance radio frequency designs, but they are far more challenging to deal with and require low levels of loss and the dielectric constant of the substrate to be crucial.

First, a copper-clad board must be acquired to create a PCB with tracks for the components.

This comprises the substrate material, commonly FR4, with copper cladding normally on both sides. A thin layer of copper sheet that has been adhered to the board makes up this copper cladding. For FR4, this bonding is often extremely strong, but because PTFE is inherently tough to bind to, manufacturing PTFE PCBs becomes more challenging.

The basic PCB manufacturing process

The next step is to make the necessary tracks on the board and remove any extra copper after the bare PCB boards have been selected and made accessible. Chemical etching is typically used to create PCBs during production by the Printed Circuit Board Manufacturer. Ferric chloride is the kind of etch that PCBs are most frequently exposed to.

The right pattern of tracks is obtained via a photography procedure. Usually, a thin coating of photo-resist is used to cover the copper on bare printed circuit boards. The appropriate tracks are then detailed on a photographic film or photo mask, which is subsequently exposed to light. In this manner, the tracks' picture is transferred to the photo-resist. Once this is finished, the photo-resist is put in a developer to ensure that it only covers the board's necessary track locations.

The printed circuit boards are then submerged in ferric chloride during the next step to etch away any unnecessary copper or track. The length of time needed for the etch is determined by the ferric chloride concentration and the thickness of the copper on the board. The photo-resist will tend to be undercut by the ferric chloride if the printed circuit boards are left in the etch for an excessively long time.

Although photographic processing is used to manufacture the majority of PCB boards from PCB Manufacturer, there are alternative options. One is to utilize a milling machine that is very specialized and exact. After that, the machine is programmed to remove the copper from the parts where it is not needed. The control is undoubtedly automated and is powered by PCB design software-generated files.

Multi-layer printed circuit boards

It is not always possible to provide all the connectivity needed using just the two sides of the PCB due to the growing complexity of electronic circuits. When thick microprocessors and other comparable boards are being constructed, this happens rather frequently. In this situation, multilayer boards are necessary.

Although multi-layer printed circuit board production follows the same procedures as single-layer board manufacturing, it necessitates a far higher level of precision and manufacturing process control.

Each layer's board is manufactured from a much thinner individual board, and these are all joined together to form the PCB. To keep the completed PCB from being excessively thick, the individual boards must get thinner as the number of layers rises. To guarantee that any holes line up, the registration between the layers must also be extremely precise.

The board is heated to cure the bonding material, which bonds the several layers together. This could cause certain warp-related issues. If large multi-layer boards are not constructed properly, they may warp. This is more likely to happen if one of the inner layers is a ground plane or a power plane, for instance.

PCB holes and vias

A PCB needs holes, also known as via holes or vias, to link the various layers at various locations. Additionally, holes could be required to allow the mounting of leaded components on the PCB. There may also be some holes that need to be fixed.

To electrically link the layers of the board, holes often contain copper layers on their inner surfaces. The plating procedure is used to create these "plated through holes." The board's layers can be linked in this manner.

When connecting the inner layers of the board, for instance, it may be required for some holes to only be present in the center of the board. Before the PCB layers are glued together, these so-called "blind vias" are drilled into the pertinent layers.

PCB solder plating and solder resist

When a PCB is soldered, it is essential to protect the parts that should not be soldered by adding a layer of solder resistance. This layer's inclusion aids in preventing unintended short circuits on PCB boards brought on by solder. The board is shielded from solder and other impurities by the solder resist, which is typically composed of a polymer layer. Typically, the solder resist has a dark green or red color.

Exposed board portions are typically "tinned" or "plated" with solder to make it easier for the components added to the board—whether lead or SMT—to solder to the board.

PCB silkscreen

On a PCB, it's frequently required to print text and add additional tiny printed indents. This can assist identify the board and designate component positions to facilitate defect discovery, among other things. After the various manufacturing procedures for the bare board are finished, the markings are added to the board using a silkscreen produced by the PCB design software.

The PCB manufacturing process is a crucial step in the lifecycle of electronic manufacturing. The adoption of several cutting-edge technological advancements in PCB manufacturing has allowed for major advancements to be achieved in the durability of the boards as well as the decrease in component and track sizes.