Ultra-thin substrate integrates ESD protection to eliminate Zener diodes

November 11, 2016 // By Nick Flaherty
TDK has developed a new ultra-thin ceramic substrate that integrates ESD protection within a multilayer structure to eliminate the need for discrete ESD components.

CeraPad provides ESD protection up to 25 kV, more than three times higher than the standard 8 kV of state-of-the-art Zener diodes and also features a high thermal conductivity of 22 W/mK that is more than three times better than that of conventional carriers, even though it is significantly slimmer with a thickness of just 300 µm to 400 µm. Depending on customer requirements, the CeraPad contact pads can be designed for both standard SAC (Sn/Ag/Cu, 260 °C) reflow processes and eutectic bonding (AuSn, 320 °C).

The new technology is especially well-suited for LED applications where the number and density of LEDs per unit continues to grow. CeraPad enables customized chip-scale packages (CSP) for standard LED elements from CSP1515 down to CSP0707. A further advantage is CeraPad's low coefficient of thermal expansion (6 ppm/mK), which is almost identical to that of LEDs. As a result, there is nearly no mechanical stress between substrate and LED when temperature changes.

Similar to printed circuit boards, CeraPad’s ceramic multilayer technology can be leveraged to design a kind of integrated circuit by interconnecting the internal redistribution layers with vias. As a rule, today’s matrix LEDs consist of several dual LEDs connected in series. By contrast, the new CeraPad module now enables for the first time a new kind of LED matrix array with up to hundreds of LED light points that can be individually controlled. Application designers will be able to use this technology to create innovative high resolution and safety-relevant light effects in the smallest of spaces, for example in multiple LED flashes in smartphones or in adaptive headlights in cars.

TDK can also provide customer-specific packaging solutions that address the future challenges of rising IC sensitivity, giving customers a promising new way to focus on light design and increasing the light efficiency of LEDs.