Common types and methods of failure analysis (FA) of electronic components

Date：2021-09-23 15:54:37Views：2658

Failure refers to the failure of electronic components. The important components of various electronic systems or electronic circuits are generally different types of components. When it needs more components, it indicates that the complexity of its equipment is higher; On the contrary, it is low. Generally, circuit failure is defined as the loss of specified functions of the circuit system. Failure analysis is the process of obtaining the failure mechanism and cause of electronic products through a series of analysis technical means such as electricity, physics and chemistry. Based on the obtained failure mechanism and causes, targeted improvement measures can be taken to improve the reliability and yield of products, shorten the R & D cycle, build a good brand, solve technical disputes and save costs.

Common types of failure analysis:

The reason for the high early failure rate is that there are unqualified parts in the product; The reason for the high late failure rate is that the product components enter the failure period after long-term use. The running in of mechanical products and the aging screening of electronic components are the measures to ensure reliability according to this failure law. Failure can be divided into temporary failure, permanent failure, sudden failure and gradual failure according to its engineering meaning, and can be divided into normal loss failure, essential defect failure, misuse failure and overload failure according to economic point of view. There are many kinds and states of products, and the forms of failure are also very different. Therefore, it is difficult to specify a unified mode for failure analysis. Failure analysis can be divided into complete machine failure analysis and parts failure analysis, and failure analysis can also be carried out according to product development stage, failure occasion and analysis purpose. The working procedure of failure analysis is usually divided into clear requirements, investigation and research, analysis of failure mechanism and countermeasures. The core of failure analysis is the analysis and disclosure of failure mechanism.

Main classification of failure analysis:

1. Failure analysis in a narrow sense: the main purpose is to find out the direct cause of product failure.

2. Generalized failure analysis: not only to find out the direct cause of product failure, but also to find out the weak links in technical management.

3. Failure analysis in new product development stage: failure analysis of failed research products.

4. Failure analysis in product trial stage: failure analysis is performed on the failed trial products.

5. Failure analysis at the service stage of finalized products: failure analysis shall be carried out for the invalid finalized products.

Failure analysis method of electronic components:

1. Pull plug

Pull out and insert method refers to monitoring the process of pulling out and inserting the component board or plug-in board, and judging whether the connection interface pulled out and inserted is the place where the fault occurs. It should be noted that when the pull-out and insertion method is used for failure analysis, there will be special conditions in the process of pulling out and inserting the component board or plug-in board, that is, the place where the state changes is sometimes not only the connection interface, but also other parts. Therefore, when applying the pull-out insertion method, we should pay attention to observe each part and subtle changes in order to make a correct judgment.

2. Sensory discrimination

The sensory discrimination method is to judge whether there is abnormality by observing the shape of parts, sensing the temperature and hardness of parts by hand touch, nose smell and smell, and ear hearing sound. Sensory discrimination method is simple and economical, but the content that can be distinguished will be restricted by sensory ability.

3. Power supply pull off

The power supply pull bias method refers to pulling the normal power supply and voltage to make it in an abnormal state, and then exposing weak links or faults, which can reflect the components and components that are faulty or on the verge of failure. This method is generally used in the case of fault caused by long working time or preliminary judgment that the fault is caused by power grid fluctuation. It is worth reminding that the power pull bias method is destructive. Before using this method, you must check the insurance coefficient or other factors. Remember not to use it casually.

4. Replacement parts

By monitoring the removed suspicious components or parts, and then replacing the qualified spare parts, compare and analyze the fault phenomena. If the fault phenomenon disappears, finally determine whether the fault source point is in the removed parts. This method is the method of replacing the spare parts.

Through the failure analysis of electronic components, diagnose the failure mechanism of failed products, take the failure mechanism as the guide, further analyze the root cause of inducing the failure mechanism, finally consider the root cause of component failure and the key factors that may affect the circuit working state, through strict tolerance design, logical reasoning The parameters of device selection are delineated in a controllable range and other targeted measures. The margin and risk of the designed circuit are controlled in the best state, and the effect of strategizing and winning thousands of miles is realized.