Failure Analysis

Published on：2018-07-02 Author：ceshi

The significance of failure analysis is mainly embodied in the following aspects: failure analysis is the necessary means to determine the failure mechanism of chip. Failure analysis provides necessary information for effective fault diagnosis.
Generally speaking, the failure of integrated circuits is inevitable in the process of development, production and use. With the continuous improvement of people's requirements for product quality and reliability, failure analysis is becoming more and more important. Through chip failure analysis, integrated circuit designers can find design defects, mismatches of process parameters or improper design and operation.
Failure analysis provides necessary feedback for design engineers to continuously improve or repair the design of chips and make them more consistent with design specifications. Failure analysis can evaluate the validity of different test vectors, provide necessary supplements for production testing, and provide necessary information basis for verifying test process optimization. The main steps of failure analysis and content chip unpacking: remove IC sealant, while maintaining the integrity of the chip function, keep die, bond pads, bond wires and even lead-frame free from damage, in order to prepare for the next chip failure analysis experiment. SEM scanning electron microscopy/EDX component analysis: including material structure analysis/defect observation, element composition routine micro-analysis, accurate measurement of component size and so on. Probe test: It is convenient and fast to obtain the internal electrical signal of IC by microprobe. Laser Cutting: Cutting off a specific area of a circuit or chip with a micro laser beam. EMMI Detection: EMMI LLM is a highly efficient failure analysis tool. It provides a highly sensitive and non-destructive fault location method. It can detect and locate very weak luminescence (visible and near-infrared light), thereby capturing the leakage current visible light produced by various component defects or abnormalities. OBIRCH Applications (Laser Beam Induced Impedance Change Testing): OBIRCH is commonly used for high and low impedance analysis in chips and leakage path analysis in circuits. The OBIRCH method can effectively locate defects in the circuit, such as holes in the lines and holes under the through holes. The high resistance zone at the bottom of the through hole can also effectively detect short circuit or leakage, which is a powerful complement to the luminescent microscopy technology.
LG liquid crystal hotspot detection: LCD detects the reorganization of molecules at IC leakage, and presents a speckle image different from other areas under the microscope, to find the leakage area (more than 10 mA fault point) that troubles designers in practical analysis.
Fixed-point/non-fixed-point chip grinding: Remove the gold bump implanted on the LCD driver chip Pad and keep the Pad intact for subsequent analysis or rebonding.
X-Ray nondestructive detection: detection of defects in IC packaging such as layer peeling, bursting, voids and wire integrity, possible defects in PCB process such as poor alignment or bridging, open circuit, short circuit or abnormal connection defects, tin ball integrity in packaging.