How to conduct secondary screening for basic electronic components? Reliability screening test method

Date：2022-08-18 15:40:53Views：915

Reliability is divided into inherent reliability and service reliability. The inherent reliability of electronic components refers to the reliability of components themselves, which depends on the reliability design of products. Due to reliability problems caused by working conditions, environmental conditions and human factors, defective components can be effectively eliminated through secondary screening of components, so as to avoid the use of defective components and effectively improve the reliability of products. This paper has collected and collated some materials, and I hope that it can be of great reference value to all readers.

Reliability of electronic components

It is difficult to avoid the defects of components. A series of non-destructive screening tests should be conducted to apply reasonable stress to eliminate the early failure products with potential defects and make them pass the early failure stage of the bathtub curve. Therefore, it is necessary to take active process measures to apply appropriate stress to the product during the whole life cycle of the product, so as to stimulate the potential defects and expose the hidden dangers in advance, so as to improve the product quality. Reliability screening can not improve the inherent reliability of products, but effective screening can feed back the defects caused by design and manufacturing to the quality control of design and production, so as to take corrective measures and truly improve the reliability of products.

Secondary screening of electronic components

The quality of the secondary screening directly affects the quality of the model products. Now, because the same device has different screening requirements in different models of products, and there are many batches and large quantities of screening devices, it often fails to meet the product requirements in terms of time schedule. Moreover, due to the limitations of screening technology, the ideal goal of eliminating all the early failure components cannot be achieved, Therefore, improving the quality and efficiency of component screening is the main objective of component screening.

Secondary screening is to conduct some tests for different failure modes to eliminate unqualified components or components that may cause early failure due to certain defects. The inherent reliability level of individual components can not be improved through secondary screening, but the inherent reliability level of batches can be improved from the perspective of production batches by eliminating unqualified products. From the perspective of environmental category, the environmental coefficient of the same type of devices in the same environment is the same, so the screening requirements for components of products in the same environment can be unified.

For example, the secondary screening items of semiconductor devices usually include appearance inspection, initial test at normal temperature, temperature cycle, constant acceleration, particle collision noise detection, intermediate test at normal temperature, high temperature aging, final test at normal temperature, low temperature test, high temperature test, sealing inspection, etc. The test methods and test conditions of each item are selected according to the relevant national military standards, and the loading stress is selected according to the standards or component specifications. Therefore, the same screening requirements can be formulated for the same components under the same environmental category to improve the screening quality and efficiency of components.

Requirements for secondary screening of electronic components

The tests of the secondary screening work and the selection of its stress are formulated according to the use requirements of the product, and the screening requirements cannot be too strict or too loose. Too strict screening requirements will eliminate the components that originally meet the product use requirements, thus increasing the screening cost and the use cost of components. In some cases, the components may be damaged, but more quality risks may be caused; If the screening conditions are too loose, the components that do not meet the product requirements will pass the customs smoothly, and the reliability of the product will be affected. Therefore, it is necessary to formulate requirements suitable for screening stress conditions, which will have a direct impact on the reliability of product quality.

The role of secondary screening of electronic components

Secondary screening can only improve the batch quality of components. Therefore, the components that have been determined to meet the requirements of the whole machine should not be screened for electrical stress, mechanical stress and thermal stress as much as possible, and only some necessary screening items for inspection and testing should be done. For example, for electronic components listed in the catalogue of qualified products of military electronic components and the catalogue of qualified manufacturers in China, if the screening items and stress conditions meet the product requirements, the secondary screening may not be conducted; The packaging form of surface mount components is generally disk sealing, which is mainly used for surface mount production lines. After screening, welding quality and reliability will be affected, so secondary screening is not appropriate. The other is selective screening for the purpose of the product. For example, the assessment of anti amplitude illumination ability is a special case. It must be considered for aerospace electronic equipment, but it can be basically ignored for ground electronic equipment.

Precautions for secondary screening of electronic components

Improper operation and protection of secondary screening can also leave hidden dangers or directly cause failure to the application of electronic components. Therefore, in the secondary screening test, the reliability of electronic components should be ensured in terms of environmental protection, operation and electrostatic protection. The stress selected for the secondary screening shall ensure that normal components will not be damaged or damaged and their service life will be significantly shortened. The temperature of the secondary screening test shall not exceed the limit temperature (including the positive limit temperature and the negative limit temperature) specified in the detailed specification of the tested components, so as to prevent the components from being damaged due to the packaging materials, structures and other reasons of the components, and its limit temperature cannot meet the temperature requirements specified in the test items. In principle, components screened under over stress conditions cannot be installed.

The arrangement of test sequence is that the later parameters can check the possible changes of components after the previous parameter tests. For the components and parts with withstand voltage and insulation resistance test requirements, the withstand voltage is first and the insulation is second, and the functional parameters are finally tested; For components with breakdown voltage and leakage current test requirements, the breakdown voltage is first, the leakage current is second, and the functional parameters are finally tested. Components with decreasing failure rate function must be suitable for screening, but not all components suitable for screening must meet this condition. With the development of miniaturization of electronic components, we should continue to expand and study new screening methods to control the quality of components, and continue to provide reliable guarantee for the reliability of electronic components used in the whole product.