A Dual Side Electroluminescence Measurement System for LED Wafer Manufacturing
H.- T. Kim, J. Kim, S. Kim, H.- K. Yuh, D.- H. Kim, D.- H. Ahn and D.- S. Shin
Affiliation: Smart System Research Group, KITECH, 35-3, HongCheon, IpJang, CheonAn, ChungNam 331-825, Korea.
A measurement system is presented for evaluating the characteristics of both sides of an LED wafer using
electroluminescence (EL). Integrating spheres (IS), photodiodes, pico-ammeters, spectrometers were installed in the front
and rear sides to measure optical characteristics with minimum EL loss. A probe was connected to a source meter with a
thin wire and attached using a transparent fixture in the front IS. The EL characteristics in a measuring point were peak
wavelength, FWHM (full width at half maximum), forward current, forward voltage and reverse current. EL images were
created by combining the motion of a stage and the EL characteristics. The correlation between the EL and the chip-level
tests and the repeatability test showed that the dual measurement is useful for LED manufacturing. Our patents were
applied to install the probe and create the EL image.
Keywords: Electroluminescence, EL imaging, epi-wafer, Optical spectrum, LED manufacturing.
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