Study On Aluminum Core AlN Thin Film For High Power LED Packaging

High-power LED is one of the most important research in lighting science and is treated as a key industry by many countries across the world. But with the high-power development of LED, thermal management becomes a big problem. And now, the material aluminum nitride (AlN) is regarded as the best solution of LED thermal management and ideal material because of its insulativity, thermal conductivity, chemical stability and other properties. This research&article’s objective is industrialization of AlN. We do a series of experiments for researching the best technological conditions of AlN manufacture and get the below goals:1. Putting forward a new idea of manufacturing AlN thin film directly on aluminum substrate by using DC reactive magnetron sputtering. In the matter of manufacturing technological conditions, we change the conditions especially for crystal structure of AlN thin film and improve the sputtering power for fast deposition of AlN in order to realize the target. At the same time, the AlN’s properties of insulativity. thermal conductivity and chemical stability can be kept to meet the requirements of LED thermal management substrate.2. Getting results of ideal technological conditions for AlN with series experiments. Sputtering Power:3A constant flow source, Sputtering Pressure:0.7Pa, N2concentration:20-25%. The deposition rate of AlN reaches14μm/h. Compared to1μm/h of other experiments, our manufacturing rate of AlN thin film has a great improvement.3. Analyzing the equivalent thermal resistance model of LED used for the theory of thermal resistance measuring. We use Ansys building and simulating the model of LED thermal management to prove the adventure of AlN thin film. What’s more, the design, manufacturing&circuit making of conductive layer are researched to complete the whole technological conditions of LED packaging substrate.4. Depositing AIN thin film with the ideal technological conditions and conductive layer by DC reactive magnetron sputtering. We got below achievements after measuring the above packaging substrate. The SEM picture and XRD result shows our AIN substrate has clear film structure and polycrystalline structure. The adhesive force between films is good (>7Mpa). The thermal resistance is3.47℃/W, far better than the common MCPCB’s9.41℃/W. Compared to the AIN ceramic’s1.98℃/W thermal resistance, our product’s thermal resistance has a small scale’s larger but much more lower cost&is fitter for the industrialization. In the measuring of insulation resistance we find that most of our products have a short circuit. We analyze the phenomenon&give some improvement suggestions.