LED wafer level packaging with a remote phosphor cap

Abstract

Phosphor converted LEDs (pc-LEDs), which employ yellow phosphor deposited on blue LEDs to generate white light illumination have been widely used in solid-state lighting (SSL). Currently most LEDs are packaged on an individual component basis. Such a conventional packaging process typically may have a relatively low throughput and poor uniformity. In this paper, a new structure for 3D wafer level LED packaging is introduced. The package consists of three parts: a silicon submount wafer with pre-mounted LEDs, a silicon cap wafer, and a layer of phosphor film. Each part was independently fabricated and subsequently assembled at the wafer level. The optical performance of singulated prototypes was characterized using an integrating sphere. Comparison and discussion of samples with various phosphor-silicone mixing ratios are given in detail.