As a core component of modern electronic devices, PCBs (Printed Circuit Boards) play an indispensable role in numerous fields, including healthcare, aviation, and telecommunications. In these critical application areas, the reliability of PCBs is of paramount importance. A high-quality PCB is not merely a matter of cost; it directly impacts the safety, performance stability, and overall reliability of the entire device.
This article will focus on the 14 key characteristics of high-reliability printed circuit boards (PCBs) and explore how to enhance PCB reliability during the manufacturing and assembly processes as well as in actual use, thereby providing more stable and reliable electronic devices for critical applications across various fields.
An Introduction to the 14 Key Features and Benefits of High-Reliability PCBs
25-micron-thick copper on the pore walls
Benefits:
– Enhance reliability and improve the Z-axis's resistance to expansion.
Risks of not doing so:
– This may result in pinholes, delamination, electrical connectivity issues during assembly, or even failures during actual use.
Repairs Without Soldering or Repairs Involving Replacing Broken Wires
Benefits:
– The flawless circuitry ensures reliability and safety, eliminates the need for maintenance, and reduces risks.
Risks of not doing so:
– Improper repairs may cause an open circuit on the circuit board, and even if repaired correctly, failures may occur under load conditions.
Cleanliness Requirements Exceeding IPC Standards
Benefits:
– Improve PCB cleanliness and enhance reliability.
Risks of not doing so:
– Residual solder and ionic residues can cause corrosion and contamination of the soldered surface, leading to defective solder joints and electrical failures, and increasing the likelihood of actual failures.
Strictly control the service life of each type of surface treatment
Benefits:
– Control the thickness of the dielectric layer to reduce deviations from expected electrical performance values.
Risks of not doing so:
– Surface treatments on old PCBs may undergo metallographic changes, leading to solderability issues, or moisture intrusion may cause delamination, open circuits, and separation of the via walls.
Use internationally recognized base materials—do not use “local” or unknown brands
Benefits:
– Improve reliability and known performance.
Risks of not doing so:
– Poor mechanical properties may result in excessive expansion, leading to delamination, circuit breaks, and warping; weakened electrical properties may result in poor impedance performance.
The tolerances for copper-clad laminates comply with the requirements of IPC-4101 Class B/L.
Benefits:
– Strictly control the thickness of the dielectric layer to improve product dimensional quality.
Risks of not doing so:
– Electrical performance may not meet specified requirements, and there may be significant variations in output and performance among components from the same batch.
Define solder mask materials to ensure compliance with IPC-SM-840 Class T requirements
Benefits:
– Ensure that the solder mask ink complies with UL standards to improve electrical insulation properties.
Risks of not doing so:
– Poor-quality ink can cause problems with adhesion, solvent resistance, and hardness, leading to the solder mask peeling away from the circuit board and increasing the risk of copper circuit corrosion and short circuits.
Tolerances for Defining Dimensions, Holes, and Other Geometric Features
Benefits:
– Strictly control tolerances and improve fits, dimensions, and functionality.
Risks of not doing so:
– Problems during assembly, such as alignment or fit, affect installation into the base.
Specify the thickness of the solder mask layer
Benefits:
– Improve electrical insulation properties and enhance resistance to mechanical impact.
Risks of not doing so:
– A thin solder mask may lead to issues with adhesion, resistance to flux, and hardness, causing the solder mask to peel away from the circuit board and increasing the risk of copper circuit corrosion and short circuits.
Defining Appearance and Repair Requirements
Benefits:
– Safety is built on meticulous care and attention to detail.
Risks of not doing so:
– Problems that are not visible on the surface may not be discovered until assembly or inspection of the final product, which can affect both the assembly process and actual use.
Requirements for Plug Hole Depth
Benefits:
– Reduce the risk of failures during assembly.
Risks of not doing so:
– If the holes are not fully filled, chemical residues from the gold plating process may remain, leading to solderability issues or even causing solder balls to splash out during assembly or actual use, resulting in short circuits.
Peters SD2955: Specified Brands and Models of Peelable Blue Adhesive
Benefits:
– Avoid using low-quality or cheap peelable adhesives.
Risks of not doing so:
– Poor-quality peel-off adhesive may cause bubbling, melting, cracking, or hardening, making it impossible to peel off or rendering it ineffective.
Follow specific approval and order placement procedures for each purchase order
Benefits:
– Ensure that all product specifications have been carefully verified.
Risks of not doing so:
– Product specifications are not thoroughly verified, leading to discrepancies that are not discovered until assembly or final inspection—by which time it is too late.
We do not accept sets of panels that contain defective units.
Benefits:
– Eliminates partial assembly to improve efficiency.
Risks of not doing so:
– Defective stencils require a special assembly procedure; assembling defective stencils wastes parts and time.
High-reliability PCBs are the cornerstone of critical applications across various fields, and their reliability directly impacts the safety and performance stability of equipment. Through an overview of 11 key characteristics, we have gained a deeper understanding of how to ensure high reliability during the PCB design, manufacturing, and testing processes. Improvements in areas such as precision design, the selection of high-quality materials, strict quality control, and durability in various environments all lay a solid foundation for PCB reliability. Furthermore, the application of new technologies, such as smart systems and IoT connectivity, opens up new possibilities for the future development of PCBs.
Through continuous improvement and innovation, PCB manufacturers will continually enhance their technical capabilities, providing more stable and reliable PCBs for high-demand applications across various fields, thereby driving the progress and development of the entire electronics industry.
