Haida International Instruments is a well-known manufacturer of reliability test equipment. Many customers come from the electronic component industry. Haida International Instruments has very mature production experience. Today, follow Haida Editor to learn more about the high and low temperature test chambers. Which aspect of the reliability test used in the component industry.
High and low temperature impact testing machine is used in electronic and electrical components, automation components, communication components, auto parts, metals, chemical materials, plastics and other industries, defense industry, aerospace, ordnance industry, BGA, PCB base board, electronic chip IC, semiconductor The physical changes of ceramic and polymer materials, testing the repeated resistance of the materials to high and low temperatures, and the chemical changes or physical damage of the product due to thermal expansion and contraction, can confirm the quality of the product, from precision IC to heavy machinery All components are used, and it is an indispensable test box for product testing in various fields.
Electronic components are the basis of the whole machine. In the manufacturing process, it may cause failures related to time or stress due to inherent defects or improper control of the manufacturing process. In order to ensure the reliability of the entire batch of components and meet the requirements of the complete machine, the components that may have initial failure under the conditions of use must be removed. The process of component failure rate over time can be described by a failure rate curve similar to a "bathtub curve". The early failure rate decreases rapidly with the increase of time, and the failure rate during the service life (or accidental failure period) is basically not change.
1. High temperature storage
Most of the failures of electronic components are caused by various physical and chemical changes in the body and on the surface, and they are closely related to temperature. After the temperature rises, the chemical reaction speed is greatly accelerated, and the failure process is also accelerated. So that the defective components can be exposed in time and removed.
High-temperature screening is widely used in semiconductor devices. It can effectively eliminate devices with failure mechanisms such as surface contamination, poor bonding, and defective oxide layers. Usually stored at the highest junction temperature for 24 to 168 hours.
High-temperature screening is simple and easy to perform, and the cost is not large, and it can be implemented on many components. After high temperature storage, the parameter performance of the components can be stabilized and the parameter drift in use can be reduced. The thermal stress and screening time of various components should be selected appropriately to avoid new failure mechanisms.
2. Power electric aging
When screening, under the combined action of thermoelectric stress, it can well expose a variety of potential defects in the body and surface of components, which is an important item of reliability screening.
Various electronic components are usually aged for several hours to 168 hours under rated power conditions. Some products, such as integrated circuits, cannot be changed at will. However, high-temperature operation can be used to increase the operating junction temperature and reach a high stress state. The electrical stress of the components should be selected appropriately, which can be equal to or slightly higher than the rated conditions, but it cannot introduce new failure mechanisms.
Power aging requires special test equipment, and its cost is high, so the screening time should not be too long. Civil products usually take several hours, military high-reliability products can choose 100, 168 hours, and aerospace-grade components can choose 240 hours or even longer periods.
3. Temperature cycle
Electronic products will encounter different environmental temperature conditions during use. Under the stress of thermal expansion and contraction, components with poor thermal matching performance are likely to fail. The temperature cycle screening utilizes the thermal expansion and contraction stress between extreme high temperature and extreme low temperature, which can effectively eliminate products with thermal performance defects. Commonly used screening conditions for components are -55～+125℃, cycle 5-10 times.
4. The necessity of component screening
The inherent reliability of electronic components depends on the reliability design of the product. In the manufacturing process of the product, due to human factors or fluctuations in raw materials, process conditions, and equipment conditions, the final products cannot all achieve the expected inherent reliability.
In each batch of finished products, there are always some potential defects and weaknesses in some products, and these potential defects and weaknesses manifest as early failures under certain stress conditions. The average life of components with early failure is much shorter than that of normal products.
Whether electronic equipment can work reliably is based on whether electronic components can work reliably. If the early failure components are installed on the complete machine and equipment, the early failure rate of the complete machine and equipment will be greatly increased, its reliability will not meet the requirements, and a great price will be required to repair.
Therefore, it is necessary to try to eliminate components with early failures as much as possible before the electronic components are installed on the complete machine and equipment. For this reason, the components must be screened. According to the screening experience at home and abroad, effective screening can reduce the total failure rate of components by 1-2 orders of magnitude. Therefore, whether it is military or civilian products, screening is an important means to ensure reliability.
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