By their very nature, printed circuit boards are intricate, delicate electronic components that must be constructed and assembled by PCB board manufacturers to extremely high standards. The many ways that can lead to PCB failure are too numerous and varied to list here; however, there are common causes that lead to printed circuit board failure. PCB designers should be aware of what these causes are so that they can take measures to avoid them at the earliest opportunity.

Common causes of PCB failure

Today, PCB board manufacturers have sophisticated printed circuit board failure analysis systems in place for diagnosing how and why a printed circuit board has failed. There are two distinct stages where failures can occur:

  1. At the PCB design and layout phase
  2. During the manufacture and assembly phase

Let’s examine both of these two phases in detail and highlight the specific areas where issues can occur: 

Avoiding failures during the PCB design phase

Even the best PCB board manufacturers, implementing the very latest production techniques, using the highest quality components and materials, may not be able to salvage a PCB layout that was poorly designed from the outset.

Such flaws can create vulnerabilities in a PCB that may only become evident under operational stress (i.e., when used in a real-world environment).

Trace Routing

One of the most common issues, as diagnosed by printed circuit board failure analysis systems, is trace routing. Where signal traces are too narrow or carry too much current for them to bear, they can overheat and potentially burn themselves open. Alternatively, traces can be packed too tightly together, which can lead to kinking and short-circuiting in high-humidity environments.

Power Distribution

As with trace routing, poorly designed power distribution can result in disruptive electromagnetic interference that can severely degrade the performance of electronics products. In instances where the coupling capacitors are placed incorrectly or where current paths are unevenly spaced, electrical instability can manifest as fluctuating system failures. Printed circuit board failure analysis may not always be able to find a precise fault when problems are intermittent.

Component Placement

Decisions relating to PCB layouts made during the design phase can introduce physical flaws that later prove fatal. Thermal management is extremely important, and printed circuit board failure analysis highlights these common component placement errors:

  • Insufficient space between heat-producing components
  • Insufficient copper / thermal vias to transfer heat
  • Non-isolated high-power PCB regions
  • Placement of ball grid arrays near critical components

Signal Integrity

Impedance mismatches, excessive stub lengths, and poor layer stackups can result in reflections, crosstalk, and jitter within high-speed circuits. Such mistakes can lead to the development of problems over time due to excessive heating or EMI emissions, which can then cascade into compliance failures and operational instabilities.

Summary of failures:

  • Trace routing problems
    • Traces too narrow → overheating, delamination, open circuits.
    • Traces too close → risk of arcing, short circuits in humidity/high voltage.
    • Sharp corners → concentrate stress, cause cracks or electrochemical migration.
  • Power distribution
    • Weak ground plane → voltage drops and ground bounce.
    • Poor capacitor placement → leading to noise, instability, and EMI.
    • Uneven current paths → place chronic stress on components.
    • Lack of thermal relief → components run too hot and fail prematurely.
  • Thermal management
    • Heat-producing components grouped too closely together → hotspots.
    • Insufficient thermal vias/copper areas → poor heat dissipation.
    • Thermal cycling → solder joint fatigue, leading to via cracking and potential delamination.
    • Sensitive components too close to heat sources → premature degradation.
  • Mechanical weaknesses
    • Large/heavy parts far from mounting points → solder joint cracks under vibration.
    • Components too closely placed at board edges → prone to damage under pressure (flexing).
    • Vias under BGAs → weaken solder pads, cracks with stress.
  • Signal integrity errors
    • Impedance mismatches → reflections, crosstalk, jitter.
    • Long stubs or poor routing → data errors at high speeds.
    • Poor stackup choices → EMI emissions, functional failures.
    • Often not visible immediately, but it reduces long-term performance.
  • Design rule violations
    • Ignoring annular ring, spacing, via aspect ratio rules → structural weak points.
    • Thin plating or voids → cracked vias under thermal or mechanical stress.
    • Boards may pass testing but fail in real conditions.

Avoiding PCB failures during the manufacture and assembly phase

PCB board manufacturers work to incredibly low tolerance levels, and they reduce error rates as much as possible. However, if mistakes are made during manufacturing assembly, all the time and effort spent on designing your printed circuit board can be wasted. 

The following manufacturing and assembly mistakes are very uncommon if you choose a leading printed circuit board manufacturer such as Bay Area Circuits; virtually all failures are eliminated via strict process control and highly disciplined quality assurance throughout all stages of manufacture and production.

Leading PCB manufacturers also have rigorous inspection procedures in place to assess and monitor production lines in real time. Here is a list of the most likely issues that can occur during manufacture and assembly:

  • Copper and plating
    • Inconsistent copper thickness → uneven currents.
    • Poor via plating → resulting in voids or cracks under stress.
    • Over-etching / under-etching → weak / shortened traces.
  • Solder mask/surface finish
    • Misaligned solder masks → shorts, exposed copper, and corrosion.
    • Poor surface finish → weak solder joints.
    • Contamination → poor adhesion, leading to failures.
  • Drilling and vias
    • Misaligned drilling → broken connections or weak pads.
    • High aspect ratio vias → difficult plating, void formation.
    • Debris left in holes → poor electrical continuity.
  • Assembly process control
    • Incorrect reflow profiles → cold solder joints or overheated components.
    • Excessive solder paste → bridging, shorts.
    • Insufficient paste → weak connections.
    • Flux residues not cleaned → corrosion, dendritic growth.
  • Component handling
    • Electrostatic discharge (ESD) mishandling → latent component damage.
    • Moisture-sensitive parts not baked → popcorning during reflow.
    • Mechanical stress during placement → cracked packages or leads.
  • Inspection and testing
    • Skipping AOI (Automated Optical Inspection) → missed solder defects.
    • Inadequate X-ray for BGAs → hidden voids or shorts undetected.
    • Weak electrical testing → defective nets pass through to customers.
  • Cleanliness and contamination
    • Ionic contamination → conductive paths, corrosion.
    • Dust or oils → poor solderability.
    • Inadequate cleaning → causing reliability issues.

Reduce error rates with Bay Area Circuits

The team at Bay Area Circuits is very happy to answer any questions you have about PCB failure rates, and with a little help from our comprehensive guide, you should have everything you need to devise a practical strategy against PCB design and production errors.

Please visit Bay Area Circuit’s website for more information: bayareacircuits.com

You can upload your PCB design files and request a quote here: instantdfm.bayareacircuits.com