| Summary: | 碩士 === 國立臺灣大學 === 機械工程學研究所 === 100 === With the development of high power LED, heat dissipation becomes a major issue of LED package. The traditional leaded package can no longer meet the demand for effective heat dissipating, so it is replaced by the SMT (surface-mount technology) with ceramic substrate. However, ceramic substrates, Al2O3 and AlN substrate, have issues of low thermal conductivity and high material cost respectively. Due to the capability of wafer-level package and low material cost provided by reclaimed wafer, the thesis provides a new option of TSV wafer as the LED package substrate.
In TSV substrate process, the innovative method with ns-laser drilling incorporating wet etching is given, and then direct plated copper (DPC) is used for pattern metallization. Si substrate requires an insulation layer of silicon dioxide (SiO2), which thermal conductivity is much lower than substrate. For this reason, the experiment is designed to analyze and compare Al2O3, AlN and Si substrate with different SiO2 thickness about thermal performance, insulation and breaking strength of substrate. Furthermore, to verify the reliability in high temperature process, high temperature test is done for TSV wafer. Then, finite element analysis software, Ansys, is applied to simulate thermal resistance and stress analysis for high power LED package with different substrates.
The experimental results reveal that TSV Si substrate shows both good performance on thermal efficiency and insulation but lower failure strength comparing with the ceramic substrate. The simulation results reveal that TSV substrate effectively reduces packaging thermal resistance and thermal stress in substrate, moreover, buffering CTE mismatch between LED die and metal core printed circuit board (MCPCB). As mentioned above, TSV Si substrate has strong potential to become the new option of high power LED package substrate.
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