High Brightness LEDs

LEDs (light emitting diodes) are light sources based on semiconductor devices. LEDs are used for a broad range of applications, such as backlight illumination of mobile phones or displays, traffic signals with low maintenance, car head lamps and rear lights, head-up displays, projectors and general illumination. They offer a number of advantages compared to other light sources, including long lifetime, low total lifecycle costs, compact size, easy implementation into end devices, and particularly, very high efficiency. The use of LEDs for illumination can save up to 85 % in energy consumption compared to standard light sources, offering the potential to reduce about 15 % of the total worldwide energy consumption if all standard light sources were substituted.

Thinning of the LED chip helps to improve the total efficiency, as it allows a more efficient cooling, enhanced light coupling out and, as an added benefit, the design of  smaller form factor devices. EV Group can build on its extensive experience in thin wafer handling technology to supports its customers in the LED market. Thin wafer handling capabilities generally enable the handling of wafers during backside grinding, where the substrate is thinned down to the single digit micrometer scale, as well as the subsequent backside processing, without any damages to the wafer.
EV Group supports two  thin wafer handling approaches:. The first approach is enabled by dedicated direct handling technologies, e.g., thin wafer robot end-effectors. The second approach is based on temporary bonding and debonding technology.

The thick and rigid device wafer is bonded onto a carrier substrate before the thinning step is performed. Now the setup is similar to a SEMI standard wafer and the backside of the device wafer can be processed. Afterwards the thin device wafer is debonded from the carrier wafer and unloaded to the desired output format. (e.g., film frame). This approach offers the tremendous advantage that thinned wafers can be processed in tools designed for wafers which have the SEMI standard thickness, thereby saving the costs for reconfiguration of these tools and guaranteeing highest flexibility for the customer.

Please see our related products EVG®850TB and EVG®850DB for detailed information.



Very thin silicon wafers (< 20 µm) show foil like behaviour. Source: EVG.