What is the role of Failure Analysis FA and destructive physical analysis DPA in component reliability test?

Date：2021-07-29 15:55:42Views：1891

Electronic components are an integral part of electronic products. Affected by the quality of electronic components, the quality and performance of electronic products will also change. Since the 1950s, reliability technology research has sprung up abroad, while it has developed since the early stage of reform and opening up in China. Through reliability test, the reliability characteristic quantity of electronic products working or stored under various environmental conditions can be determined to provide useful data for use, production and design; It can also expose the problems existing in the design, raw materials and process flow of the product. Through a series of feedback measures such as failure analysis and quality control, the existing problems of products can be solved gradually and the reliability of products can be improved.

Failure analysis (FA)

From the late 1960s to the early 1970s, the U.S. military adopted the component quality assurance plan centered on failure analysis, exposed problems through manufacturing and testing, found out the causes through failure analysis, improved design, process and management, and then repeated cycles of manufacturing, re testing, re analysis and re improvement, so that the failure rate of integrated circuits increased from 7 in 6 to 7 years × 10-5 / h down to 3 × 10-9 / h, the failure rate of integrated circuit has been reduced by 4 orders of magnitude, and the "militia II" intercontinental missile program and Apollo spacecraft lunar landing program have been successfully realized. It can be seen that FA plays an indispensable role in various major projects. To sum up, the main functions of FA are as follows:

1) The theory and idea of improving design, process or application are obtained through FA.

2) By understanding the physical phenomena causing failure, the formula of prediction reliability model is obtained.

3) It provides theoretical basis and practical analysis means for reliability test (accelerated life test, screening) conditions.

4) When dealing with the problems of components encountered in the project, provide decision-making basis for whether to use the whole batch.

5) The implementation of FA corrective measures can improve the yield and reliability, reduce the faults during system test and operation, and obtain obvious economic benefits.

Destructive physical analysis (DPA)

As a supplementary means of failure analysis, DPA is a test conducted by a third party or user with certain authority during product delivery acceptance test. Its main feature is to analyze qualified components.

Role of DPA: how to reduce defects is an important part of reliability work in PCBA processing plant. Even qualified products may have defects. The analysis of qualified products is to investigate and evaluate the defects of electronic components with good characteristics by using the same technical method as failure analysis. In the second screening test, taking the measures of sampling and analyzing the qualified products, it is easy to find the defects of electronic components early, so as to feed back to PCBA manufacturers to improve and improve their production technology. DPA helps to find abnormal batch products to ensure the reliability of installed products。

in general,These are conducive to rejecting electronic components with batch defects, so as to better ensure the reliability of products.Carrying out DPA and FA in the secondary screening test plays a very important role in the quality assurance and reliability improvement of major engineering products.

Failure caused by other human factors

In the screening and testing process of electronic components, there are mainly the following failures:

1) Improper program setting causes the detection failure of electronic components;

2) Failure of components due to reverse polarity connection;

3) Component failure caused by wrong signal;

4) Electrical stress overshoot causes component failure;

5) Failure of electronic components caused by misuse of adapter;

6) Mechanical stress failure caused by improper plugging mode;

7) Some components with polarity are placed upside down by mistake during storage.

As we all know, electronic components are one of the main factors affecting the quality of electronic products. If there are problems with electronic components, the quality must be greatly affected. In the screening of electronic components, we should pay attention to quality control, overall consideration, scientific selection, simplified design, rational use of performance parameters of components and give full play to the function of electronic components. Reasonable selection according to favorable conditions, simplifying circuit design, improving reliability and derating can improve the reliability of products.