Failure analysis of LED light strip chip
Date:
2020-11-06


As the core component of LED light source, the quality of LED chip determines the performance and reliability of the product. Chip manufacturing process as many as dozens or even hundreds of channels, complex structure, small size (micron level), any process or structure abnormalities will lead to chip failure. At the same time, the chip is relatively fragile, any improper use may damage the chip, making the chip failure in the process of use. The analysis of chip failure is very complex and needs many technical methods.


Generally, the failure causes of LED light strip chip can be divided into the following categories:


1. Influence of packaging process

LED packaging is mainly used to protect LED chips, the quality of packaging directly affects the use of chips.


2. Over electric stress

LED chips are sensitive to electricity. Over current use, static electricity, lightning strike, power grid fluctuation and poor LED power supply will cause over electric stress damage to the chip, resulting in chip failure.


3. External environmental impact

The LED chip is relatively fragile. The water vapor and corrosive gas in the environment will make the chip leakage, electrode corrosion and other problems, and the chip will fail. LED chips must be packaged before they can be used. When the LED chips are in an extremely harsh environment, the general packaging body can not effectively protect the chip.


Failure analysis of LED light strip chip


4. Poor heat dissipation of LED lamps and lanterns

LED chips are very sensitive to temperature, and some even say that 'the life of LED chips is shortened by half when the temperature is increased by 10 ℃. LED lamps and lanterns have poor heat dissipation. As a heat source, the temperature of LED chips will increase sharply, the life will be greatly shortened, and even the chips will be overheated and burned. For the chip failure caused by poor heat dissipation (visible LED chip infrared thermal image thermal distribution case).


5. Abnormal chip technology

The chip structure is very complex, and its manufacturing process steps can be as many as dozens or even hundreds. The instability of process parameters will cause process abnormalities (such as unclean etching or over etching of passivation layer, poor aluminum coating, unclean photoresist cleaning, etc.), which may affect the reliability of the chip and cause chip failure in subsequent use.


6. The chip structure design is unreasonable

If the chip structure design is not reasonable, the current density distribution will be uneven, the light conversion efficiency will be low, the overall heating capacity will be large, and the local current congestion will occur. When the chip is in normal use, the current crowding area is heated seriously, the temperature is high, the chip aging is rapid, and the life is greatly reduced; when there is an EOS impact, the current density in the current congested area will increase rapidly, and the breakdown failure phenomenon will appear first.


7. Quality problems of chip epitaxy

The core of LED chip work is epitaxial layer. The quality of epitaxial layer of LED chip is related to the chip life, anti-static ability and anti-electric stress ability.


Basic LED light chip failure is the above reasons, for more information about LED, please pay attention to magic light net.


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