A PCB Quality Checklist for Optimized Board Manufacturing

The English language is extensive and full of various synonymous words or words that convey the same meaning. The converse is also true. Some words may be interpreted in different ways. Then, there are words that always mean the same thing but can be interpreted differently. One such word is quality. Quality is always intended to provide an indication of how well something meets its intent. Yet, quality may be poor, average or good.

 

The word “quality” is often used in the context of PCBs. But, what exactly does it mean when we say that a board is of good or high quality? Are we referring to the design or the components used? Or the quality of the board materials? Or of the fabrication and PCB assembly processes? Or all of these? Moreover, how do you know if your board is in fact of good quality? By first defining what is meant by “quality,” we should be able to create a PCB quality checklist that will allow for a definitive answer to the question of whether our manufactured boards achieve optimality.

What is PCB Quality?

The design and manufacturing of custom PCBs is a complicated process. As such, it consists of many aspects, each of which may impact the overall board quality. Let’s take a look at these factors and the impact they can have.

Factors that Impact PCB Quality

• Design

PCB quality begins with the design. Obviously, the design has to meet the circuit operation and performance criterion; however, the quality of the manufactured board determines reliability or how well these objectives are met and for how long.

• Components

The quality of the components that you select for your board is a critical factor. Inferior or counterfeit components may eventually fail and cause premature repairs or replacements that translate into additional cost or lost revenue. Additionally, if your component listing or bill of materials (BOM) is inaccurate, you will likely suffer extended turnaround times and unnecessary costs.

• Materials

Another important factor is the quality of the materials you choose for your board. For different board types, certain board properties are more important. For example, controlling impedance, which is impacted by the dielectric constant and trace parameters, is critical for high-speed designs.

• Fabrication

The physical construction of your board determines its structural integrity or ability to last throughout its intended lifecycle. The quality of the process is significantly dependent on the materials used, as well as the quality of your design file. Incomplete or inaccurate design data and information can delay your board’s manufacture or even prevent it from being manufactured at all.

• Assembly

PCB assembly, or PCBA, is the final manufacturing stage in the development process where the components are attached to the board. As such, it is probably preferable that your contract manufacturer (CM) outsources fabrication instead of outsourcing assembly. PCBA is heavily influenced by the design and fabrication stages; yet, this is the stage where the overall board quality is verified. A substandard process may result in boards that do not meet your performance and operation standards or are unreliable in the field.

The overall quality of your board is defined by the quality of each of the aspects listed above. Failure to meet reasonable quality standards for any of these will result in a substandard final product. Conversely, achieving the highest quality for each of these can result in an optimally manufactured PCB.

A PCB Quality Checklist for Board Manufacturing

Above, we have defined PCB quality as a comprehensive assessment of the entire development process, which we can reasonably describe in terms of a set of significant aspects of the process. Now, we can put forth a PCB quality checklist based on ensuring those aspects are optimized for quality, as shown below.

PCB Quality Checklist

	Design Make quality a priority during design. This means ensuring that your design decisions are made with a focus on aiding your CM in the optimization of your board’s manufacture.
	Components Choose components that meet your performance and durability criteria, are from reliable sources, and are replaceable with like components that meet these qualifications. Also, ensure your BOM is accurate.
	Materials Choose materials where the parameters and your trace widths, lengths, and copper weights are optimized to meet your board type’s requirements.
	Fabrication Acquire and follow your CM’s rules and guidelines for DFM. Verify compliance by liberally using a Design Rule Checker (DRC) throughout your PCB layout design and ensure that your design file package is complete.
	Assembly Make good use of design for assembly (DFA) rules and guidelines to aid your CM in securely attaching your components to your board. Ensure that your component footprints are accurate for the components of your BOM and follow board clearance requirements.