Process technology and integration of an LED driver using chip-embedding technology

System integration for LED lighting is facing the challenge of providing many additional smart functions in one housing of small form factor. A possible way to integrate more functionality into smaller volume is a system in package (SiP) approach which combines e. g. logic and power chips. Chip-embedding in laminate technology based on copper leadframes is an attractive technology for SiP. In this paper we show how to enable chip-embedding technology to integrate both logic and power functions in one package. As key enablers we identified diffusion soldering die-attach for power dies, laser direct imaging for structuring of low parasitic redistribution layers, warpage and distortion compensation, and complexity reduction in material processing. We present the results of a functional LED light engine built with our flexible 3D-SiP approach based on chip-embedding in laminate. The footprint of the light engine's power supply subsystem could be reduced by a factor of 3.8 in comparison to using standard packaged components. We verified a process chain for 3D-assembly of surface mount devices on top of the chip-embedding package, and for soldering of this 3D-SiP to the light engine board. The manufacturability of the 3D-SiP we demonstrated in a productive surface mount technology line.