Description of test items and significance of chip failure analysis

Date：2021-09-17 17:47:20Views：1265

With the progress of science and technology, intelligent products are increasing day by day. From computers and smart phones to automotive electronics and artificial intelligence, we can see them everywhere in our production and life. The key to their development is the semiconductor chip that drives the internal transceiver. Due to the continuous improvement of product quality and reliability requirements, failure analysis is becoming more and more important. Chip failure analysis can help IC designers find design defects, mismatch of process parameters or improper design and operation. Next, let's look at the chip IC failure analysis test.

The failure of IC integrated circuits is inevitable in the process of development, production and use,The significance of IC failure analysis is mainly reflected in the following aspects:

1. Failure analysis is a necessary means to determine the chip failure mechanism.

2. Failure analysis provides necessary information for effective fault diagnosis.

3. Failure analysis provides necessary feedback information for design engineers to continuously improve or repair the chip design and make it more consistent with the design specifications.

4. Failure analysis can evaluate the effectiveness of different test vectors, provide necessary supplements for production testing, and provide necessary information basis for verification and test process optimization.

Main steps and contents of failure analysis

IC unsealing: remove the IC sealant, keep the chip function intact, and keep die, bond pads, bond wires and even lead frame from damage, so as to prepare for the next chip failure analysis experiment.

SEM / SEM / EDX composition analysis: including material structure analysis / defect observation, conventional micro area analysis of element composition, accurate measurement of component size, etc.

Probe test: quickly and conveniently obtain the internal electrical signal of IC with microprobe. Laser cutting: cutting a line or a specific area on the upper layer of a chip with a micro laser beam.

Emmi detection: Emmi low light level microscope is a highly efficient failure analysis tool, which provides a highly sensitive and non-destructive fault location method. It can detect and locate very weak luminescence (visible light and near-infrared light), so as to capture the visible light of leakage current caused by various component defects or abnormalities.

OBIRCH application (laser beam induced impedance value change test): OBIRCH is commonly used for high impedance and low impedance analysis inside the chip and line leakage path analysis. Using OBIRCH method, defects in the circuit can be located effectively, such as holes in lines and holes under through holes. The high resistance area at the bottom of the through hole can also effectively detect short circuit or leakage, which is a powerful supplement to the luminescence microscopy technology.

LG liquid crystal hot spot detection: the liquid crystal is used to sense the molecular arrangement and reorganization at the IC leakage, showing a mottled image different from other areas under the microscope, so as to find the leakage area (fault point exceeding 10mA) that puzzles the designer in the actual analysis.

Fixed point / non fixed point chip grinding: remove the gold bump planted on the LCD driver chip pad and keep the pad intact for subsequent analysis or rebinding.

X-ray nondestructive detection: detect various defects in IC package, such as layer peeling, burst, cavity and wire integrity, possible defects in PCB process, such as poor alignment or bridging, open circuit, short circuit or abnormal connection, and tin ball integrity in package.

Sam (SAT) ultrasonic flaw detection can carry out non-destructive detection on the internal structure of IC packaging, and effectively detect all kinds of damage caused by water vapor or heat energy, such as: 1. Delamination of wafer surface; 2. Cracks in tin ball, wafer or glue filling; 3. Air holes in packaging materials; 4. Various holes, such as holes at wafer joint surface, tin ball, glue filling, etc.

This article introduces this. In view of the great changes in the modern electronic assembly industry, the process requirements are higher, the product reliability is paid more and more attention, the investment scale is larger and larger, and the requirements for production and testing equipment are higher and higher. It is generally based on the failure mode and phenomenon, through analysis and verification, simulate and reproduce the failure phenomenon, find out the cause of failure, and dig out the failure mechanism. It has strong practical significance in improving product quality, technology development and improvement, product repair and arbitration of failure accidents.