Meaning
Industrial standard issued by the JEDEC Solid State Technology Association that defines the conditions for high temperature storage life testing of solid state devices. This document known as jesd22-a103 provides a uniform method for evaluating the effect of prolonged exposure to heat on the reliability of integrated circuits and other electronic components. It specifically focuses on storage conditions where no electrical bias is applied to the device, allowing the test to isolate the impact of thermal stress on the materials and the internal structures.
The standard establishes several stress levels, categorized by temperature and duration, which manufacturers use to qualify their products for different market segments. By following these guidelines, companies can ensure that their products will remain functional even after being stored in harsh environments for extended periods.
Standard Condition
The protocol specifies several distinct temperature grades ranging from 125 degrees celsius to as high as 200 degrees celsius for specialized applications. A typical qualification run for standard consumer electronics might involve testing at 150 degrees celsius for 1000 hours. The jesd22-a103 standard requires that the temperature in the test chamber be maintained within a tight tolerance, usually plus or minus five degrees, to ensure the validity of the data.
Samples are placed in the chamber in a way that allows for uniform airflow around each component, preventing the formation of hot or cold spots. Before the test begins, the devices are checked for functionality to establish a baseline. After the specified duration, the samples are cooled down to room temperature and re-tested.
Any device that fails to meet its original electrical specifications is considered a failure. This systematic approach allows for a direct comparison between different batches and different suppliers.
Degradation Mechanism
High temperature storage exposes the components to several failure modes that are driven by the movement of atoms and the expansion of materials. Under the conditions described in jesd22-a103, the internal bonds between the silicon chip and the package can weaken due to the growth of intermetallic layers. In lead-free solder systems, the heat can cause the formation of tin whiskers or the coarsening of the grain structure, both of which can lead to electrical shorts or mechanical breaks.
The standard is particularly effective at identifying problems with the molding compound, such as outgassing or the loss of adhesion to the lead frame. Moisture trapped inside the package can also expand and cause delamination or “popcorning” effects. By stressing the device without the complexity of electrical signals, engineers can pinpoint which material interfaces are the most vulnerable to thermal aging.
This knowledge is then used to refine the package design and select more stable materials for future product iterations.
Qualification Protocol
Following the procedures in this document is a requirement for any semiconductor company wishing to sell components into the global supply chain. The jesd22-a103 test is often part of a broader reliability qualification suite that includes moisture sensitivity, temperature cycling and electrostatic discharge testing. A successful pass on the high temperature storage test indicates that the device has a robust physical structure and that its chemical components are compatible over the long term.
Large manufacturers in China use these results to provide a guarantee of quality to their international customers. The test reports must include the specific temperature grade used, the duration of the test and the sample size, as well as a detailed analysis of any failures that occurred. If a failure is found, a root cause analysis is conducted to determine if the issue was a manufacturing defect or a design flaw.
This rigorous process ensures that only the most reliable components reach the final assembly line. The final certification of a product often depends on its ability to withstand the maximum storage conditions defined by the standard.
