Development of a “Flip Glass Substrate” LED package technology for color bin yield and view angle enhancement

This study presents a “Flip Glass Substrate” LED package design. The transparent glass is employed as the substrate. This LED package architecture and process has two merits, (1) Large view angle: Light is allowed to emit in all directions for the LED packaged in a flip glass-substrate. (2) Color bin yield enhancement: CIE (The International Commission on Illumination) chromaticity coordinate distribution (CCx, CCy) of glass-substrate coated with phosphor could be evaluated before LED chip package. Thus glass-substrate with wrong chromaticity coordinates could be reworked in early stage (like the concept of known-good-die). Moreover, the advantage of remote phosphor is also achieved for this package architecture. In application, the glass substrate for packaging is implemented and tested. Measurements show the chromaticity relation between unpackaged-LED and packaged-LED is determined as 0.017 in CCx. The view angle of packaged device can reach 142°.