As the foundation for connecting and supporting electronic components, the quality and reliability of PCBs are critical to the performance of the entire device. In this article, we’ll explore the 10 characteristics of highly reliable PCBs as explained by PCB manufacturers, so you can better understand how to select and evaluate high-quality PCBs.
1. Copper thickness on the pore walls: 20 μm
Benefits: Improve reliability, including enhancing the Z-axis's resistance to expansion.
The Risks of Not Doing So: Insufficient copper thickness on the hole walls may lead to blowholes or degassing, electrical connectivity issues during assembly (separation of inner layers, hole wall fractures), or potential failures under load conditions during actual use.
2. Repairs without soldering or repairs involving the replacement of broken wires
Benefits: A flawless circuit ensures reliability and safety—no maintenance, no risks.
The Risks of Not Doing So: If the repair is not done properly, it can cause an open circuit on the circuit board. Even if the repair is done ‘properly,’ there is still a risk of failure under operational conditions (such as vibration), which could lead to a failure during actual use.
3. Use internationally recognized brand-name panels; do not use low-quality, unbranded products.
Benefits: Improve reliability, service life, and known performance.
The Risks of Not Doing So: Using low-quality board materials will significantly shorten the product’s service life. Furthermore, poor mechanical properties of the board materials mean that the circuit board cannot perform as expected under assembly conditions. For example, high expansion rates can lead to delamination, open circuits, and warping, while weakened electrical properties can result in poor impedance performance.
All materials used at Jingpeng Circuit’s PCB factory are sourced from well-known domestic and international board suppliers, with whom the company has established long-term strategic partnerships to ensure a stable supply.
4. Use high-quality ink
Benefits: To ensure the quality of printed circuit boards, improve the realism of image reproduction, and protect the circuitry.
The Risks of Not Doing So: Poor-quality ink can lead to problems with adhesion, solvent resistance, and hardness. All of these issues can cause the solder mask to peel away from the circuit board, ultimately resulting in corrosion of the copper circuits. Poor insulation properties can cause short circuits due to unintended electrical connections or arcing.
5. Cleanliness Requirements Exceeding IPC Standards
Benefits: Improving PCB cleanliness improves reliability.
The Risks of Not Doing So: Residue and solder buildup on printed circuit boards pose a risk to the solder mask; ionic residues can cause corrosion and contamination of the soldered surfaces, which may lead to reliability issues (defective solder joints/electrical failures) and ultimately increase the likelihood of actual failures.
6. Strictly control the service life of each type of surface treatment
Benefits: Solderability, reliability, and reduced risk of moisture ingress.
The Risks of Not Doing So: Since the surface treatment of older circuit boards undergoes metallurgical changes, solderability issues may arise, while moisture ingress can lead to problems such as delamination, separation of inner layers from via walls (open circuits), and other issues during the assembly process and/or actual use. Take the surface tin-plating process as an example: a tin-plating thickness of ≧1.5 μm ensures a longer service life.
7. High-Quality Plug Holes
Benefits: High-quality via plugging at PCB factories will reduce the risk of failures during the assembly process.
The Risks of Not Doing So: If the holes are not fully filled, chemical residues from the gold plating process may remain inside them, leading to issues such as poor solderability. Furthermore, tin balls may be trapped inside the holes; during assembly or actual use, these tin balls may be ejected, causing short circuits.
8. The tolerances for copper-clad laminates comply with the requirements of IPC 4101 Class B/L.
Benefits: Strictly controlling the thickness of the dielectric layer can reduce deviations from expected electrical performance values.
The Risks of Not Doing So: Electrical performance may not meet the specified requirements, and there may be significant variations in output and performance among components from the same batch.
9. Strictly control tolerances on external dimensions, holes, and other geometric features
Benefits: Strictly controlling tolerances improves the dimensional quality of products—enhancing fit, form, and function.
The Risks of Not Doing So: Problems during assembly, such as alignment and fit (issues with press-fit pins are only discovered once assembly is complete). In addition, due to increased dimensional deviations, there may also be problems fitting the component into the base.
In accordance with high-reliability standards, hole position tolerance is ≤0.075 mm, PTH diameter tolerance is ±0.075 mm, and dimensional tolerance is ±0.13 mm.
10. The solder mask is sufficiently thick
Benefits: Improves electrical insulation properties, reduces the risk of peeling or loss of adhesion, and enhances resistance to mechanical impact—no matter where the impact occurs!
The Risks of Not Doing So: A thin solder mask can lead to issues with adhesion, flux resistance, and hardness. All of these problems can cause the solder mask to peel away from the circuit board, ultimately resulting in corrosion of the copper traces. Poor insulation caused by a thin solder mask can lead to short circuits due to unintended electrical conduction or arcing.
Selecting a highly reliable PCB with the characteristics listed above is a critical step in ensuring the outstanding performance of electronic devices. These characteristics include appropriate copper thickness on via walls, the absence of solder repairs, the use of well-known board materials, high-quality ink, cleanliness requirements that exceed IPC standards, control over the service life of surface treatments, high-quality via plating, compliance with tolerance requirements, and a sufficiently thick solder mask.
By paying attention to these details, you can ensure that your PCBs maintain high reliability across a wide range of applications.
Frequently Asked Questions
What features should I look for when selecting a PCB?
When selecting a PCB, you should consider characteristics such as the copper thickness of the via walls, serviceability, board quality, ink quality, cleanliness, surface treatment, via plating quality, tolerance requirements, and solder mask thickness.
Why is cleanliness important for PCB reliability?
Cleanliness can affect the quality of soldering and electrical connections; poor cleanliness may lead to solder joint issues and electrical failures.
What are some well-known PCB board suppliers?
Some well-known PCB substrate suppliers include Rogers Corporation, Isola Group, and Panasonic Electronic Materials.
How can you determine if the solder mask layer on a PCB is thick enough?
The thickness of the solder mask should be determined based on the specific application requirements and standards; generally speaking, a sufficient solder mask thickness provides better electrical insulation properties and mechanical strength.
Can I perform soldering repairs on a PCB?
Avoid soldering repairs whenever possible, as they may damage the circuit board. The best practice is to ensure the quality and reliability of the PCB during the manufacturing process.
For more information about high-reliability PCBs or advice on selecting PCBs, please feel free to contact us. We are here to provide you with support and consultation.
