Heterogeneous packaging for mixed LED and electronic packages

We present results of a study on heterogeneous packaging of mixed LED dies and electronic dies. Our investigations have targeted the requirements for co-existence of LEDs and electronics, package design based on QFN technology (which is a major standard in electronics) and definition of a roadmap for package encapsulation methods and materials. LED based lighting enables lighting products to become both digital and connected, with as a consequence that more and more electronic functionality might become part of LED modules. The clear division between separately packaged LEDs and packaged electronics will fade. Packages containing electronics will appear which are characterized by co-existence of LEDs and electronics, increased function density, multi-(LED)-die content, integrated optical features and hybrid materials. As a carrier to study the aforementioned aspects, LED packages with basic electronic functions were selected. The packages contain LED dies and electronic dies in one circuit. External switching signals applied to the electronics, result in routing of the current through the circuit via different paths. The two-compound (2K) encapsulation of the package serves two functions: covering the electronic dies and defining a reflective cavity, translucent for the light emitted by the LEDs. Both parts/materials not only need to comply with package encapsulation requirements, but also with light extraction, reflection and (optionally) light conversion and beam-shaping requirements. Packages with various encapsulation material combinations are fabricated, soldered on a co-designed test-board and characterized with respect to light-output and thermal performance.