Chip Scale Packaging (CSP), originally from the semiconductor industry, continues to make headlines in the LED industry. At LightFair 2015, I saw many companies showcasing CSP products with flip-chip technology such as Lumileds, Seoul Semiconductor, Lumens, LG Innotek, Edison Opto, and Samsung. Other companies also using this technology include Epistar, Genesis Opto, Lextar and Toshiba.
The advantage of CSP is that it is done at the wafer level, therefore eliminating the traditional LED packaging because it doesn’t need the wire bonding, sub-mount or lead frame. Therefore, you have a smaller footprint, wider beam angle, more design flexibility and it can be overdrived. Theoretically, this should lead to higher reliability and lower cost than a traditional package, but this hasn’t quite been the case. CSP is usually used for 1W~5W high power products, but it is currently not as efficient as a high power package. Also, some early released products were up to 3 times the cost of a similar packaged LED, so there is still room for improvement.
The penetration rate is also still low mainly because of the yield. The phosphor film which replaces the phosphor coding process can easily fall off. In addition, packagers need to invest in the new equipment and cooperate with LED chip makers. So far, most of the production is being done by the LED chip players who are buying the new equipment and producing it by themselves. However, if they are not vertically integrated, it takes more time to tune the CSP process because they lack the packaging experience. Pure package players, on the other hand, don’t have the intention to invest in this new process, given the existing tools and as a result, the cost is still high and few packagers are adopting this technology.
End of 2015/beginning of 2016 was when many of the companies listed said they would have commercially available products so it will be interesting to see what the price differentials are as well as the differences in efficiency and reliability.