2. Modern electronic assembly technology primarily focuses on PCBA as its core. Consequently, research on the reliability of electronic assembly technology is centered around the failure phenomena observed in PCBA.
3. The failure phenomena of PCBA can be classified into two categories: those that arise during production and those that occur during the user’s service.
4. (1) Failure phenomena of PCBA (either internal or surface) during the manufacturing process include issues such as plate explosion, delamination, surface excess, ion migration, and chemical corrosion (rust), among others.
5. (2) Various failure modes and manifestations on PCBA during user service encompass problems like virtual welding, brittle fracture of solder joints, deterioration of microstructure in solder joints, and overall reliability degradation.
6. The objective of failure analysis is to identify the cause of the failure, gather and analyze data, and summarize and eliminate the failure mechanisms responsible for the malfunction of a specific device or system.
The primary aim of failure analysis is:
▪ To identify the root cause of the failure;
▪ To trace adverse factors within process design, manufacturing, and user service;
▪ To recommend corrective actions to prevent future failures.
By leveraging the insights gained from failure analysis, we aim to continuously enhance process design, optimize manufacturing practices, and improve product usability, thereby achieving a comprehensive increase in product reliability.
**PCBA Failure Rate Curve**
1. The failure rate curve for PCBA products encompasses three levels:
▪ **Component Failure Rate Curve:** By subjecting components to forced aging prior to shipment, we can significantly reduce their failure rates during the user’s service period.
▪ **Component Supply Life Curve:** This curve illustrates the service life of components from the user’s perspective and has a profound impact on the reliability of the overall system.
▪ **PCBA Assembly Failure Rate Curve:** This is influenced by three elements: the lifespan of incoming SMD materials, the assembly life of SMDs, and the longevity of solder joints. Ultimately, the lifespan of a PCBA is primarily determined by the durability of its solder joints. Thus, ensuring high-quality soldering for each joint is crucial for maintaining system reliability.
2. **Typical Instantaneous Failure Rate Curve of PCBA**
The typical instantaneous failure rate for PCBA, referred to as the PCBA typical failure rate, represents the likelihood of failure within a specific time frame after the component has been operational for time t. This curve consists of three segments: the premature aging zone, the product service zone, and the aging zone.
**Levels, Principles, and Methods of PCBA Failure Analysis**
1. **Levels of Failure Analysis**
In the production and application of electronic products, the management and analysis of PCBA and solder joint failures closely resemble the reliability control and analysis techniques applied to other systems.
2. **Principles of Failure Analysis—Foundation of Mechanistic Reasoning**
▪ On-site data collection;
▪ Retesting (failure mode confirmation) analysis;
▪ Examination of failure mechanisms tied to specific processes and structures;
▪ Investigation of failure mechanisms linked to specific environments;
▪ Understanding the connection between failure modes and their underlying mechanisms;
▪ Long-term accumulation of pertinent knowledge and experience.
3. **Failure Analysis Methods**
Experts in the PCBA industry have compiled effective analysis models for the methods employed in PCBA failure analysis.
The above outlines common approaches for analyzing PCBA board failures as shared by PCBA manufacturers.
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