Development and Analyses of High-Reliability, High-Efficiency and High-Brightness LED Flip-Chip Packages and Modules

The application of LED (Light Emitting Diode) of converting the electron current into the light through the p-n junction of semiconductor diodes has became popular in the world wide. The high-power LEDs typically used in the markets, such as illumination, signaling, screen backlights and automotives, have potential to penetrate into the general lighting market because of their advantages of energy saving and environmental friendliness. However, the issues of requiring low cost, high power dissipation, high efficiency and good reliability, have to be resolved before this huge applications. The objective of this study is to develop low-cost high-brightness flip-chip LED packages and array modules with high efficiency and reliability. The thermal, mechanical and optical behaviors of flip-chip LED packages and array modules are investigated numerically and experimentally in order to come up with innovative technologies and optimized products. In the pre-study, the thermal and environmental reliability tests of flip-chip LED packages have been carried out, and thermal resistance and the resulting failure modes were documented. The thermally-induced strains and stresses of the packages have been analyzed in transient and steady states using a finite element method with thermo-mechanical models. Their optical fields have been simulated by Trace Pro software in order to improve the efficiency. In the first phase of this project, mechanical properties (such as elastic modulus, CTE, and strength) of packaging materials will be characterized by DMA, TMA and material testing machine. The thermal conductivity of the substrates and thermal interface materials will be characterized using thermal-conductivity equipments. The flip-chip LED array will be proposed, analyzed, assembled and verified through a series of prototyping tests in terms of thermal resistance, reliability and illumination efficiency. In the second phase, a lighting module associated with novel flip-chip LED array packages will be developed, analyzed and tested in terms of thermal dissipation, reliability and illumination fields in order to hopefully end up with new technologies and innovative flip-chip LED array lighting modules with high efficiency, brightness, and reliability, but with low cost.

Project ID:PB9907-10772
External Project ID:NSC99-2221-E182-016-MY2