| Summary: | 碩士 === 長庚大學 === 機械工程學系 === 101 === The purpose of this research is to the material interfacial strength and
the reliability of LED package. According to previous researches and
literature, the oxidation and delamination of materials affect the reliability
severely. This study is mainly divided into two parts: the first part is to
study the bonding strength of silicone (with and with anti-precipitation
powder) and other materials (leadframe and plastic materials). From the
results of Peeling Test, the bonding strength of silicone with
anti-precipitation powder lowers to 70% of the original. And the bonding
strength between silicone and leadframe is 5~10 times higher than the
bonding strength between silicone and plastic material. The second part is
to study the oxidation of materials interface by long-life-time reliability
test and thermal shock test. After life-time reliability test, some LED
packages appear dark and delaminated. By the XPS (X-ray Photoelectron
Spectroscopy) analysis, it is fund the dark surface is due to oxidation.
Under 85℃ environment and powering for a long time, the packages with
the silicone of high oxygen permeability have oxidation phenomenon,
while there is no oxidation phenomenon under 85℃/85%RH environment,
because the oxygen permeability is preventol by absorbing moisture.
However, there is no oxidation phenomenon for package with the silicone
of low oxygen permeability. In the thermal shock test, they are the same
phenomena. To use the silicone of high oxygen permeability will cause
materials oxidation in high temperature shock, but not in low temperature
shock. So, we can infer that the high temperature and high oxygen
permeability are the main cause to the oxidation phenomenon.
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