Electronic Components：General procedure for failure analysis

• Definition: Diagnose the failure of electronic components

1.Conduct electrical measurements ,use advanced physical, metallurgical and chemical analysis methods.

2.The purpose of failure analysis is to determine the failure mode and failure mechanism, and propose corrective measures to prevent the recurrence of failure mode and failure mechanism.

3.Failure mode means the phenomenon and forms of failure, such as open circuit, short circuit, parameter drift, functional failure and so on.

4.The failure mechanism means the failure of the physical and chemical processes, such as fatigue, corrosion and over stress.

• General procedure for failure analysis

1.Collect spot data.

2.Do the Electrical measurement and determine the failure mode.

3.Nondestructive inspection.

4.Open the package.

5.Mirror inspection.

6.Power-on and locate the failure points.

7.Physical and chemical analysis of the failure site to determine the failure mechanism.

8.Comprehensive analysis, determine the cause of failure, put forward corrective measures.

•DETAIL

1.Collect spot data

2.electrical measurement and determine the failure mode

The Electrical failures can be divided into connectivity failure, electrical parameter failure and functional failure.

Connectivity failures include open circuit, short circuit, and resistance change. This type of failure is easy to test, and most field failures are caused by electrostatic discharge (ESD) and over-stress (EOS).

Electrical parameters failure,It needs more complex measurements, the main forms of this include ：

1.a parameter value exceeds the specified range (tolerance)

2.parameter instability.

Confirm the function is invalid, you need to input a known excitation signal to the components and measure the output result. If the measured output and the expected state are the same, the components function are normal .On the contrary,they are inactive.The functional testing is mainly used for integrated circuits.

There is a certain correlation between the three types of failure. One failure may cause other types of failures. The causes of functional failures and electrical parameter failures can often be attributed to connectivity failures. In the condition of  lacking complex functional test equipment , it is possible to use simple connectivity tests and parametric test methods for electrical measurement, combined with the application of physical .You also can acquire satisfactory results.

 3.non-destructive examination

X-ray inspection means that safely using X-ray (multi-directional and angle optional) to detect the packaging of components, such as bubbles, bonding line anomalies, grain size,etc.

1.Applicable situation: To check whether the abnormal bonding, the package with or without defects, to confirm the grain size and layout.

2.Advantages: short duration, intuitive and easy to analyze.

3.Disadvantages:The information accessed is limited.

4.Limitations:The damage or defects in the internal wiring are difficult to check and must be obtained through functional tests and other tests.

Case Study: X-Ray detection ---- bubble, bonding line

X-Ray authenticity identification ---- empty bomb (shown in the figure, there is no grain)

X-Ray is used for the analysis  of  sources (the same model number in the same brand of chip)

(The dense dot is the BGA’s tin beads. we can see that the chip is actually BGA secondary package)

4.open the package

There are two methods to open the package,the first one is mechanical methods and the last one is chemical methods. According to the packaging materials to classify, microelectronic device package types include glass packaging (diode), metal shell packaging, ceramic packaging, plastic packaging,etc.

5.micro-morphology technology

Optical microscopy analysis

The Secondary Electron Image Technique of Scanning Electron Microscope

Failure Location Technology of Voltage Effect

 Author ：Ferdinand Rinol— WIN SOURCE ELECTRONICS