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Several Common Types Of Automobile PCB Die Causes

Mind Electronics Limited | Updated: Aug 10, 2017

Several common types of Automobile PCB die causes
 At present, the Automobile PCB technology is increasingly mature, since its launch has long been the advantages of long life has been one of the focus of public attention. But in recent years, in the Automobile PCB production and application, we still encounter a lot of "dead light" phenomenon. The so-called dead lights, also known as the lights, is the Automobile PCB light source does not shine. Whether it is production or application of the dead lights, are manufacturers are very troublesome problem, it is necessary to face the loss of product bad, but also affect the consumer confidence in the Automobile PCB products. Therefore, some of the common causes of Automobile PCB die analysis and analysis, help us to reduce and prevent the failure of Automobile PCB products occur repeatedly to protect product quality and improve product competitiveness, but also for enterprise technology to improve and enhance the reference, So as to create greater economic benefits for enterprises.
Common Automobile PCB dead light causes the following are the following:
Weld line breakage
For the "dead light", first of all we should determine whether the Automobile PCB is short or open, if it is open, we will generally consider the Automobile PCB light inside the wire is broken. Automobile PCB lights inside the wire break, resulting in no PCB power supply voltage, which is one of the common causes of automotive die die. There are five places where the common line is broken, as shown in Figure 1, A, B, C, D, E points:
The position of the weld fracture can be checked by cross-section analysis of the sample using an optical microscope and an electron scanning microscope (SEM), which facilitates further reason analysis.
As the thermal expansion coefficient of silica gel and gold wire is quite different. After 100 cycles of hot and cold impact test, the silica gel and gold wire are constantly expanding and contracting, and the gold line solder joint is the stress concentration point, so the most likely to cause The solder around the solder burst, the cracking of the silicon wire leads to the weakest break of the solder joint, the final sample appears dead lamp.
2. Removal of solid crystal layer
For some of the vertical chip using Automobile PCB lamp beads, the bottom of the solid crystal layer and the stent coating is a more common cause of death. The reason for the death of the lamp beads is the phenomenon of peeling between the encapsulation glue and the stent interface. The degree of peeling and the area are extended with the use of the process, which further causes the peeling of the solid crystal and the stent, resulting in the death of the sample. It is also possible that the adhesive adhesion of the encapsulation glue causes a layering between the encapsulated glue and the stent interface.
3. solder joints burned
In some cases, the lamp beads die is not necessarily the problem of the lamp itself, there may be caused by the use of power supply.
Lamp lamp death lamp is the root cause of the use of the lamp during the surge current is too large, because the chip P area resistance value is higher than the N area, when the current through the P electrode, P electrode first burned and lead to open dead lamp. Lamps used in the process of surge current (or voltage) is too large, it is likely with the lamp drive power in the start or off when the surge current, there may be chip P electrode wire is flawed, resulting in P electrode solder joint Instantaneous contact with the bad situation, when there are more than one Automobile PCB series will accumulate high pressure in contact with bad contacts caused by instantaneous high current caused by lamp beads wire burning and sealing black.
4. Chip is subject to corrosion
Dead lights in addition to open the phenomenon, there are short-term dead lights phenomenon. When the coexistence of heat and water vapor will corrode the chip electrode, resulting in chip electrode metal corrosion and electrode line adhesion decreased, and even lead to local area off. And the migration of the electrode dissolved material will make the chip P, N electrode short circuit lead to die dead.
There are many reasons for the death of the Automobile PCB, from the packaging, application, to the use of all aspects of the phenomenon may be dead lights, the above mentioned case is just initiate. How to reduce and eliminate deadlocks, improve product quality and reliability, is every Automobile PCB enterprises need to face the key issues. Through the analysis of the cause of the death of the Automobile PCB is one of the important ways to reduce and eliminate the dead LED of the car, while the failure of Automobile PCB products, in addition to powerful equipment hardware, but also need to have the chip, Link production experience as a support, in order to play the equipment capacity for customers to solve problems