PCB Manufacturing

Circuit Board Manufacturing Process: A Comprehensive Guide for Beginners

Circuit Board Manufacturing

A circuit board physically supports and mounts electronic components in fixed arrangements. It provides an interconnection (an electrical connection) between the system’s electronic components on conductor paths etched on the board’s surface.

The electronic circuit is divided into sections called stages. It connects the individual stages so that the device will operate as intended. A modern circuit board has layers of insulating material and one or more conductive pathways (‘tracks’)-etched or printed onto the insulating material. These pathways connect electronic components (such as transistors, resistors, and integrated circuits).

Printed circuit boards (PCBs) are the primary component of all major electronic equipment. These devices support every major electronic component in the industry, from the one-sided boards used in the earliest days of electronics to the latest multi-layer boards that support today’s high-speed and high-frequency applications.

The following article is about the detailed circuit board production process so that the reader understands exactly how these devices can make their electronic dreams come to life.

Circuit Board Manufacturing Process From Design to Finish

Let’s talk about the entire circuit board manufacturing process.

1. Design and Layout

The circuit board manufacturing process begins with its design and layout. Designing is done using advanced Computer-Aided Design (CAD) software and is essential. It requires the designer to have the vision to see problems before they are present and provide a convenient and cost-effective way to find a solution.

Potentials, such as signal interference, thermal management, and space constraints, must be anticipated. Electrical parameters, component placement, and routing paths must also be considered.

The goal is to produce the best possible circuit board manufacturing blueprint and create a strategic plan that maximizes performance and minimizes costs.

design and layout

2. Material Selection

The second step of the circuit board manufacturing process is to select material. Choosing a base material for a board is critical. FR4, a glass-reinforced epoxy laminate, is the typical designer choice known for its excellent electrical insulation and mechanical strength.

Materials like polyimide are essential for flex applications, as these materials bend and twist, and boards are bent during final application assembly. However, the truth is that cost depends upon the substrate chosen and the ability of any material to properly manage heat.

Advanced materials, like the global family of Roger’s laminates, are an excellent example. They are used in high-frequency circuits and are crucial in selecting the proper substrate to solve specific operational needs while considering the appropriate cost and performance needed.

3. Photolithography

Photolithography is the third step of circuit board production. A photomask transfers the design from the board onto the substrate during this stage. A non-conductive substrate is covered with a photosensitive film.

Once the design overlaps this film, it is exposed to UV light. The circuit patterns are defined when the exposed areas harden, and the unexposed areas are dissolved, that is, removed, in the developing process.

So, this is how the patterns are drawn and why the circuits are so small and intricate versus when they were simply straight lines.

4. Etching

Following photolithography, the substrate is placed into an etching bath. This is the fourth step in circuit board production. The unwanted copper is removed, leaving the copper that comprises the conductive circuitry.

The etching can be performed in several ways, e.g., chemical etching, where an acidic or basic corrosive solution dissolves the unprotected copper.

Precision is critical in the etching process. Any imperfections can result in a malfunctioning board. Advancements in etching, like laser etching, have been crucial since they offer enhanced precision and the added capability to form complex, multi-layer circuits, which has been critical in the evolution of circuit board manufacturing.

4. Drilling

Drilling is the fifth step in the circuit board manufacturing process. Holes are drilled for the component leads, which connect the multiple layers of the board. Unlike the preceding phases, where the equipment follows professional, software-controlled equipment performs the drilling automatically.

Like the other phases, the drilling is critical. Any inattention could result in a short, damaging the board and/or its components.

The board is then plated with a thin layer of copper. This process will plate the board’s surface and the holes’ inside. A layer of copper will be very conductive and ensure the electrical connection will not fail.

Circuit Board Manufacturing

5. Component Mounting

Component mounting has changed substantially in the circuit board manufacturing process over the past few decades. What was initially employed through-hole technology (THT) is now generally performed using surface-mount technology (SMT). SMT allows far more components to be placed upon a much smaller surface area.

Moreover, This is why, generally, SMT is used in place of THT. In SMT, the components are placed onto the board’s surface, and their leads are soldered to the board’s pads.

These advances have been brought about through the pressures of the industry. Simply, more and greater functionality must be available in ever-shrinking spaces.

6. Soldering

Soldering is physically securing components to the board by creating strong, reliable electrical connections. Various techniques are used, from reflow soldering, used with SMT components, to wave soldering, used with THT components.

The choice of soldering method in the circuit board manufacturing process is not casual, instead, it depends on the type of components, the board’s design, and the production volume. Reflow soldering, in particular, has become very popular, as it is fast and efficient, particularly for creating uniform solder joints in high-volume production.

The evolution of these techniques, such as lead-free solders and selective soldering machines, is a testament to the industry’s ongoing commitment to environmentally sound and precise manufacturing.

PCB Soldering

7. Quality control

Quality control is one of the most critical phases of the circuit board manufacturing process. In this phase, every board must pass the rigorous performance specifications and reliability standards required by manufacturers of the latest cutting-edge technology.

There are many different testing methodologies used to ferret out defects and faults. These include automated optical inspection (AOI), in-circuit testing (ICT), and functional testing.

The emphasis on quality control is ensuring that the customer receives a product that operates reliably in their application. A product with as solid and secure a reputation as consumer products should.

8. Surface Finishing

The last stage in the circuit board manufacturing process is the application of a protective coating, typically a solder mask, which protects the board from environmental forces and electrical shorts. It covers the board and provides a recognizable appearance; green is the most common colour, but it can be any of several colours, depending on the application.

As well as this, silk-screening for the component identifications is done now. The care and attention to detail in the finishing process stand as a metaphor for the entire circuit board manufacturing process and guarantee the long-term usability of the board.

 

Conclusion

Despite its complex look, the circuit board production process is a straightforward operation requiring basic knowledge, common materials, and simple equipment. Anyone may now design and build useful electrical devices. Computers, robotics, thermometers, and sensors all rely on circuit boards.

Following the methods outlined here will allow you to learn a few fundamental circuit board manufacturing abilities and begin working on your projects.

This refers to the basic set of abilities that most beginners can develop to the point that they can use their understanding of electronics and the art and science that underpins it.

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