Thermal Characterization and Reliability Assessment of Chip Scale Packaged Light-Emitting Diodes with High Color Rendering Index

This paper reports thermal characterization and reliability assessment of CSP LEDs with high color rendering index (>95). The high CRI CSP LEDs obtained by optimization of current flow, ohmic contact, and phosphor concentration. The EOS level of CSP LED improved by modification of internal structure. The current spreading of CSP LED enhanced by increasing number of fingers along vertical direction, and as a result, junction temperature of CSP LED also decreased. Phosphor concentration for encapsulation of CSP LED optimized through two different operating test conditions. CSP LED with relatively low phosphor concentration shows better reliability and estimated lifetime of 5.7326×10
⁴
hours.