Via-hole-type flip-chip packaging to improve the thermal characteristics and reliability of blue light emitting diodes

Ho Young Kim, Chang Man Lim, Ki Seok Kim, Jeong Tak Oh, Hwan Hee Jeong, June O. Song, Tae Yeon Seong, Hiroshi Amano

Research output: Contribution to journalArticle


We investigated the effect of via-holes in the lead-frame on the reliability of blue flip-chip light-emitting diodes (FCLEDs). For bonding, conventional Sn-Ag(3.0%)-Cu(0.5%) solder (SAC) and Ag sintered paste were adopted. Lateral LED, conventional FCLED (c-FCLED), and via-hole FCLED gave efficacies of 218.5, 221.6 and 225 lm/W at 30 mA. The lateral LED sample (bonding material: silicone), c-FCLED sample (SAC), via-hole-type sample (Ag sinter), and via-hole-type sample (SAC) exhibited total thermal resistance of 15.24, 10.19, 8.95, and 11.79 K/W, respectively. The humidity/temperature/H2S gas reliability examinations showed that unlike the via-hole-type samples, the lumen of the c-FCLED was fallen by 15.0% after exposure for 500 h. Furthermore, the c-FCLED exhibited a 19.6% higher forward voltage than the via-hole FCLED after 1,000 thermal-cycles. SEM results showed that unlike the via-hole type FCLED, the c-FCLED underwent cracking after thermal cycle of 1000 times.

Original languageEnglish
Pages (from-to)P165-P170
JournalECS Journal of Solid State Science and Technology
Issue number9
Publication statusPublished - 2019 Jan 1


ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

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