IEEE Access (Jan 2021)

Epoxy Molding Compound Lead Frames With Silicone Resin for Encapsulating AlGaN-Based UVB Light-Emitting Diodes

  • Tsung-Yen Liu,
  • Shih-Ming Huang,
  • Mu-Jen Lai,
  • Rui-Sen Liu,
  • Yi-Tsung Chang,
  • Wen-Hong Sun,
  • Ray-Ming Lin

DOI
https://doi.org/10.1109/ACCESS.2021.3111258
Journal volume & issue
Vol. 9
pp. 129874 – 129880

Abstract

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In this paper we report epoxy molding compound lead frames (EMC-LFs) with encapsulated silicone as a simple and inexpensive packaging for AlGaN-based ultraviolet-B (UVB) light-emitting diodes (LEDs) displaying high light extracting efficiencies (LEE) and long operation lifetimes. The convex surfaces and beveled shapes obtained after curing the encapsulated silicone surrounding the UVB-LED chips significantly enhanced the light output power (LOP). With silicone present inside the EMC-LFs having bonding cavity diameters of 1.7 and 1.45 mm, the LOPs of the UVB-LEDs improved by 26 and 42%, respectively; reliability tests performed over a period of 1000 h revealed, however, that the LOPs decreased to 70 and 71%, respectively, of their initial values, but no cracks appeared in the silicone during such long-term operation. Thus, the stability of silicone-encapsulating EMC-LFs for UVB-LEDs was acceptable. When compared with AlN-based direct plating copper ceramic lead frames (AlN-DPC-LFs), our proposed packaging structure and method have the potential to lower the manufacturing cost of UVB-LEDs.

Keywords