What is a weld cavity? Why do weld voids occur? What should I do about solder voids?
During a recent trial production phase of a new customer order, our engineers discovered signal loss and increased noise during high-frequency signal transmission in the electronic assembly (PCBA) manufacturing process.
What are solder voids? Solder voids are pockets of gas or air that form inside solder joints when electronic components are attached to the substrate through the solder paste printing and reflow soldering process in surface mount technology (SMT).
Voids created during the solder paste printing reflow process can have a negative impact on the performance and reliability of electronic products. Some of the major problems that can be caused by voids include:
1. Affecting electrical performance: Voids can increase the resistance of the solder joint, leading to reduced electrical performance of electronic devices, signal transmission loss, increased noise, and other issues.
2、Reducing the strength of the solder joint: Voids decrease the actual contact area between the solder and the substrate and components, which in turn reduces the mechanical strength of the solder joint and increases the risk of solder joint fracture.
3、Leading to poor thermal conductivity: Voids decrease the thermal conductivity of the solder joint, affecting the heat dissipation of the component and potentially causing overheating and reduced performance.
4、Accelerating fatigue failure: Voids can serve as initiation points for the fatigue failure of solder joints. With thermal cycling and mechanical stress, voids may expand and lead to solder joint fractures.
5、Affecting reliability: Voids can compromise the reliability of the solder joint, potentially increasing the failure rate of electronic devices in harsh environments.
Causes of solder voids
There are various factors that can lead to voids in the solder paste printing reflow process, some of the main causes include:
1、Air bubbles: Air bubbles trapped in the solder paste can expand during reflow soldering, forming voids once the solder paste melts. The presence of air bubbles may stem from the manufacturing, storage, or printing processes of the solder paste.
2、Volatile components: Volatile components in the solder paste release gas during heating, and if they do not evaporate adequately, voids can form.
3、High reflow temperature: Excessive reflow temperatures may cause the volatile components in the solder paste to evaporate rapidly, creating voids.
Solution
To reduce or prevent the occurrence of voids, the following methods can be implemented:
1. Optimize the solder paste printing process: Select the appropriate solder paste viscosity, printing pressure, speed, and cleaning frequency to ensure smooth and even spread of solder paste on the substrate during printing.
2. Use the correct solder paste: Choose the right type of solder paste to minimize the formation of voids. High-quality solder paste can help reduce the formation of air bubbles within the paste, thereby minimizing voids.
3. Optimize the preheat stage: Adjust the preheat temperature and time appropriately so that volatile components and gases in the solder paste can fully evaporate during the reflow process.
4. Optimize the reflow process: Adjust the reflow temperature, duration, and speed to ensure complete melting of the solder paste and establishment of a good connection with the pad, while allowing ample time for air bubbles within the solder paste to escape.
5. Perform inspection and quality control: Utilize X-ray inspection equipment to assess solder quality, and make necessary adjustments and improvements upon identifying void issues.
WellCircuits has been dedicated to delivering highly reliable electronic assembly and manufacturing services for over 16 years, with a focus on sectors such as medical, renewable energy, automotive electronics, security, communications, and AI. The core technical team boasts over 20 years of experience in electronic product design, development, and manufacturing, having served more than 300 customers across various industries in over 40 countries and regions worldwide with dependable electronic assembly services.
During a recent trial production phase of a new customer order, our engineers discovered signal loss and increased noise during high-frequency signal transmission in the electronic assembly (PCBA) manufacturing process.
What are solder voids? Solder voids are pockets of gas or air that form inside solder joints when electronic components are attached to the substrate through the solder paste printing and reflow soldering process in surface mount technology (SMT).
Voids created during the solder paste printing reflow process can have a negative impact on the performance and reliability of electronic products. Some of the major problems that can be caused by voids include:
1. Affecting electrical performance: Voids can increase the resistance of the solder joint, leading to reduced electrical performance of electronic devices, signal transmission loss, increased noise, and other issues.
2、Reducing the strength of the solder joint: Voids decrease the actual contact area between the solder and the substrate and components, which in turn reduces the mechanical strength of the solder joint and increases the risk of solder joint fracture.
3、Leading to poor thermal conductivity: Voids decrease the thermal conductivity of the solder joint, affecting the heat dissipation of the component and potentially causing overheating and reduced performance.
4、Accelerating fatigue failure: Voids can serve as initiation points for the fatigue failure of solder joints. With thermal cycling and mechanical stress, voids may expand and lead to solder joint fractures.
5、Affecting reliability: Voids can compromise the reliability of the solder joint, potentially increasing the failure rate of electronic devices in harsh environments.
Causes of solder voids
There are various factors that can lead to voids in the solder paste printing reflow process, some of the main causes include:
1、Air bubbles: Air bubbles trapped in the solder paste can expand during reflow soldering, forming voids once the solder paste melts. The presence of air bubbles may stem from the manufacturing, storage, or printing processes of the solder paste.
2、Volatile components: Volatile components in the solder paste release gas during heating, and if they do not evaporate adequately, voids can form.
3、High reflow temperature: Excessive reflow temperatures may cause the volatile components in the solder paste to evaporate rapidly, creating voids.
Solution
To reduce or prevent the occurrence of voids, the following methods can be implemented:
1. Optimize the solder paste printing process: Select the appropriate solder paste viscosity, printing pressure, speed, and cleaning frequency to ensure smooth and even spread of solder paste on the substrate during printing.
2. Use the correct solder paste: Choose the right type of solder paste to minimize the formation of voids. High-quality solder paste can help reduce the formation of air bubbles within the paste, thereby minimizing voids.
3. Optimize the preheat stage: Adjust the preheat temperature and time appropriately so that volatile components and gases in the solder paste can fully evaporate during the reflow process.
4. Optimize the reflow process: Adjust the reflow temperature, duration, and speed to ensure complete melting of the solder paste and establishment of a good connection with the pad, while allowing ample time for air bubbles within the solder paste to escape.
5. Perform inspection and quality control: Utilize X-ray inspection equipment to assess solder quality, and make necessary adjustments and improvements upon identifying void issues.
WellCircuits has been dedicated to delivering highly reliable electronic assembly and manufacturing services for over 16 years, with a focus on sectors such as medical, renewable energy, automotive electronics, security, communications, and AI. The core technical team boasts over 20 years of experience in electronic product design, development, and manufacturing, having served more than 300 customers across various industries in over 40 countries and regions worldwide with dependable electronic assembly services.
