Solving CSP LEDs' thermal challenges

January 30, 2017 // By Julien Happich
With its patented electro-chemical oxidation (ECO) process, Cambridge Nanotherm claims it can addresses the unique needs of chip-scale packaging (CSP) LEDs.

For typical CSP LEDs, the challenge is conducting the concentrated thermal flux through the dielectric layer of the PCB to which the LED die is attached and into the metal board where it can be spread and removed by a heatsink. Multi-chip PCBs are usually made of an epoxy resin mixed with ceramic to create a thermally conductive, but electrically isolating, barrier. However, there’s a limit to how much ceramic can be added before the composite become friable, restricting the thermal conductivity of the layer.

Cambridge Nanotherm’s ECO process converts the surface of an aluminium board into a super-thin alumina dielectric layer. This nanoceramic alumina has a thermal conductivity of 7.2 W/mK, which, coupled with being just tens of microns thick, makes for a composite thermal performance of 115 W/mK — much higher than any competitive MCPCB. This means the heat from the CSP LEDs is conducted efficiently through the dielectric and into the aluminium board, ensuring the LED junction temperature is kept at a stable temperature. The company has recently expanded its manufacturing capabilities to meet increasing demand for its thermal management technology.

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