UVC LED continued to heat up the market became hot.We all know that UVC LED sterilization effect is significant, 

in a certain dose and distance, it only takes a few seconds to dozens of seconds to kill common bacteria.However, 

what we do not know is that with the hot market, various UVC LED application products on the market emerge at 

the right moment, some of them are shoddy, often the same level of UVC LED products, the actual use effect is 

very different.

In the final analysis, it is the difference of technology and craft.

This issue of UVC LED packaging technology science will start from the thermal management, UVC LED packaging 

technology behind the secret.

Thermal management,

The key to improving the life of UVC leds

Like any electronic component, UVC leds are sensitive to heat.

The external quantum efficiency (EQE) of UVC leds is relatively low, only about 1-3% of the input power is converted 

to light, while the remaining 97% or so is basically converted to heat.At this point, if the heat is not removed quickly, 

keep the LED chip below its maximum operating temperature, will directly affect the chip's service life, or even can 

not be used.It can be said that thermal management is the key to improve the service life of UVC LED.

Good thermal management,

The emphasis is to reduce the welding cavity rate

Due to the small size of UVC leds, most of the heat cannot be dissipated from the surface, so the back of the LED 

has become the only way to effectively dissipate heat.At this point, how to do a good job in the packaging joint thermal 

management is particularly important.

When it comes to the thermal management of packaging, it is inseparable from two aspects, one is the material, the 

other is the process.

In terms of materials, after years of development, the current UVC LED on the market is basically a flip chip with high 

thermal conductivity aluminum nitride substrate.Aluminum nitride (AIN) has excellent thermal conductivity 

(140W/ mk-170w /mK), can withstand the aging of the ultraviolet light source itself, to meet the requirements of UVC 

LED thermal management.

In terms of technology, there are several ways to solidify crystals on the market.The first is the use of silver slurry, 

this way although the binding force is good, but easy to cause silver migration, resulting in device failure.The second 

way is to use solder paste welding, this way because the solder paste melting point is only about 220 degrees, after 

the device patch, there will be re-melting phenomenon, chip is easy to fall off and fail, affecting the reliability of UVC 

LED.As a result, most of the market is the use of a third method of solidification: the use of gold - tin eutectic welding.

Compared with the previous two solid-crystal methods, eutectic welding is mainly carried out by flux, which can effectively 

improve the bonding strength and thermal conductivity of chip and substrate, and is more reliable, which is conducive to 

the quality control of UVC LED.

Since the packaging materials of UVC LED on the market are mostly the same as the solid-crystal process, why do the 

effects of thermal management differ so much?

At this point, the weld void rate has to be mentioned.

The welding cavity rate simply refers to the defects formed in the welding process between LED chip and substrate, which 

are unable to be welded in some areas due to the influence of technology and so on. The defects appear to be hollow in 

appearance, which is an important indicator affecting heat dissipation.