Multilayer ceramic capacitor failure modes
Multilayer ceramic capacitors (MLCCs) are essential components in modern electronics. They are valued for their reliability, compact size, and efficiency. Despite their widespread use, these components are susceptible to degradation and even failure. This article breaks down common multilayer ceramic capacitor failure modes including low insulation resistance (IR), low capacitance, mount failure, and appearance defects. It also explores what often causes these issues, whether from manufacturing processes or how the capacitors are used.
Useful life of a multilayer ceramic capacitor
The performance and reliability of a multilayer ceramic capacitor over time are determined by the useful life of a component.The useful life of these capacitors depends on factors like operating temperature, applied voltage, and mechanical stress. Manufacturers specify lifetime ratings in datasheets based on standardized test conditions. Exceeding these conditions can shorten the capacitor’s lifespan, leading to performance degradation or failure.
There are various failure mechanisms through which MLCCs can degrade or fail over time, affecting circuit performance. Failures can result from electrical, mechanical, or environmental stress, often linked to factors like excessive voltage, temperature, or physical damage. Understanding these failure modes helps engineers design more reliable circuits and prevent unexpected component issues. Some of the most common MLCC failure modes include low insulation resistance, cracking, low capacitance and appearance defect.
1. Low insulation resistance
Low insulation resistance (IR) in multilayer ceramic capacitors (MLCCs) occurs when the capacitor allows excessive leakage current, reducing its ability to block DC flow. One common cause is surface leakage, often due to moisture contamination or ionic residues from improper cleaning during manufacturing. These contaminants create conductive paths across the capacitor’s surface, leading to reduced IR and potential circuit malfunction.
Internal leakage is another key cause of low IR. It results from defects within the ceramic dielectric, such as microcracks, voids, or dielectric breakdown. These defects can compromise the insulating properties of the material, allowing current to pass through the capacitor layers. Over time, this failure mode can worsen, leading to significant performance degradation or complete failure of the capacitor. Figure 1 shows insulation resistance of a multilayer ceramic capacitor decreasing as a function of time due to degradation.

2. Low capacitance
Low capacitance in MLCCs can occur due to physical damage, such as a cracked or broken capacitor. Mechanical stress during handling or mounting can fracture the ceramic layers, reducing the effective capacitance or rendering the component non-functional. This type of damage often results from improper board design, excessive bending, or thermal shock during soldering.
Contact failure at the terminations can also lead to low capacitance. Poor solder joints, oxidation, or fractures in the termination layers can disrupt the electrical path between the capacitor and the circuit. Additionally, capacitance can drop due to voltage or temperature effects. High DC bias can compress the ceramic material, lowering capacitance, while extreme temperatures may alter the dielectric properties, reducing the capacitor’s effectiveness.
3. Cracking
Cracking is a common MLCC failure mode caused by mechanical or thermal stress. Mechanical stress often results from improper handling during assembly or excessive board flexing after installation. These stresses can create fractures in the ceramic dielectric, compromising the capacitor’s insulation and performance. Figure 2 shows a cracked multilayer ceramic capacitor.

Thermal stress can also lead to cracking. Rapid temperature changes during soldering or operation can cause expansion and contraction of the materials at different rates. This mismatch can form cracks that grow over time, leading to reduced insulation resistance, increased leakage current, or even catastrophic failure.
4. Mount failure
Mount failure in MLCCs can occur due to issues during the mounting process. Mount trouble often results from misalignment or insufficient solder coverage during PCB assembly. This can lead to weak mechanical connections, causing intermittent contact or complete detachment under stress or vibration.
Poor solderability is another common cause. Contaminated terminations or improper soldering temperatures can prevent a reliable bond. Tombstoning, where the capacitor stands on one end during reflow soldering, also contributes to mount failure. It happens when uneven heating causes one side to reflow faster, disrupting the balance of surface tension.
5. Appearance defect
Appearance defects in MLCCs can indicate structural issues that affect reliability. Broken capacitors often result from mechanical stress during handling or assembly. Cracks can form, compromising the dielectric material and increasing the risk of electrical failure.
Chipping occurs when small pieces break off the capacitor’s edges, usually due to impact or improper mounting pressure. This can expose internal layers, reducing insulation resistance. Shape and dimension defects, such as irregular sizes or warped bodies, can affect proper placement on the PCB, leading to poor solder joints and mounting failures.
Mitigating multilayer ceramic capacitor failure modes
To mitigate low capacitance and low insulation resistance in MLCCs, it’s important to choose high-quality components from trusted manufacturers. Proper storage matters too—keep capacitors in a dry, controlled environment to avoid moisture absorption, which can lead to performance issues. Quality control during manufacturing also plays a key role in reducing these risks.
To minimize cracking in MLCCs, it is essential to handle components carefully during assembly and avoid excessive mechanical stress. Proper mounting techniques, including ensuring even solder application and avoiding excessive board flex, can reduce the risk. Additionally, engineers should account for thermal expansion and contraction during design, using appropriate thermal profiles during soldering and ensuring that capacitors are rated for the operating temperature range. Proper storage and handling, along with following manufacturer guidelines, further help prevent cracking.
Appearance defects can often be avoided with careful handling. Cracks, chipping, and size variations can happen from rough storage or mishandling during assembly. Automated optical inspection (AOI) helps catch these issues early, while proper training for assembly staff can prevent damage during manual handling.
To reduce the risk of mount failure, follow recommended soldering profiles and use the right solder paste and volume. Proper component alignment during placement is crucial to avoid issues like tombstoning or poor solder coverage. Techniques like flexible PCB design and strain relief can help absorb stress, preventing cracks from mechanical strain.