Mar 20, 2017: Chip-scale packages (CSPs) are new to the LED industry, but are the mainstay of the traditional semiconductor industry, where they improve reliability, thermal management and enable smaller packages.
CSP LEDs can be less than a tenth of the size of high and middle power LEDs, increasing power density and simplifying integration into final products. This new architecture can also lower thermal resistance, improve reliability and widen viewing angles compared to other traditional packages.
However, there are also several challenges to overcome at the device manufacturing and module integration levels. These include color uniformity, chemical stability, given there is little to no sealing off from the external environment, and control of optical properties like the radiation pattern. In this context, Yole Développement estimates that CSP LED modules represented less than 1% of the LED module business in 2016. However, with strong potential in multiple applications and the lighting industry getting experience with integrating such technology, we forecast a market share of nearly 6% by 2021.
This report provides a comprehensive analysis of CSP LED devices, with analyses including: chip and package technology, manufacturing processes, related costs/prices, industry and market trends. The report details deeply analyses CSP LED lighting module design, with focuses including: optical design, thermal and electrical management and precautions for CSP LED integration.
After smartphones and TVs, a potential revolution in general and automotive lighting
CSP LEDs add value through power density offered from a small surface. The first targeted application was smartphone flashes. As smartphones get thinner and add functions, so too must integrated components/modules.
The small form factor and wide beam angle of CSP LEDs have also driven their use in TV backlighting units. Wide beam angles mean the pitch between LEDs can be larger, reducing the number of devices needed and in turn lowering backlight cost.
But CSP LEDs are also a means to develop new functions in lighting products. Some general lighting applications are likely to adopt these light sources to reduce the cost of the lamp/luminaire. Their small size enables LED clusters, similar to chip-on-board (COB) LED modules but with more functionality. CSP LED clusters promise tunable white, human centric light (HCL), intended to promote a person’s well-being, mood and health, and others smart lighting functions.
Last but not least, high luminance and uniformity will mean CSP LEDs enter automotive headlamp applications, which requires high intensity and beam shape control. New developments in matrix headlamps will include CSP LEDs to increase matrix resolution, enhance driver vision and improve Advanced Front Light Systems (AFLS) in combination with cameras. In this report, Yole Développement maps the CSP LED application landscape. It analyses CSP LED lighting module performance in general lighting applications, identifying opportunities, describing case studies, and comparing positioning against other module technologies.
CSP LED application landscape
Simplified manufacturing process impacts the supply/value chain
CSP LED technology eliminates some package assembly and die attach stages. This is likely to benefit to LED chip manufacturers, who can develop packages and supply them directly to LED module manufacturers more easily, bypassing their traditional customers, and so increasing their profits. Vertically integrated LED manufacturers can also decrease their packaging costs. However, adopting the technology requires development of new expertise, modifying the traditional packaging landscape. For example, phosphor and encapsulant deposition processes will move from dispensing to phosphor sheet/film deposition or molding. This evolution affects equipment and material suppliers, who have to develop new solutions.
Operationally, Lumileds was the first company to commercialize LEDs in CSP format in 2013. The company was rapidly followed by several other players, mostly Taiwanese. But some others, like Osram, still have doubts about the necessity of such technology, and instead are positioned toward traditional middle and high power LEDs, including COBs.
This debate is also relevant at the LED module level, where CSPs cause some difficulties. For example, during PCB design, special care should be given to copper traces and solder masks for optimum performance. Some critical properties, like their small soldering surfaces and sideways light emission, may impact module integration. And while the benefits of CSP LEDs are not yet clear for them, they question the real opportunity of this solution.