LED封装散热关键技术研究

LED lighting is a hot in technological research nowadays. With continuous improvement of LED luminous efficiency and LED drive current increasing substantially, thermal management has become the biggest obstacle to the commercialization of high power LED. Thermal management is a key issue in the high-power LED package, which has great effect on the output power and lifetime of the device. Putting forward a new method that prepares alumina insulating layer directly on aluminum substrate, and then sputters conductive film on the insulating layer to prepare a new kind of metal core printed circuit board with high-thermal conductivity. The effect of process parameters (current density, concentration of sulfuric acid,temperature and time) on the thermal resistance, thickness, insulation resistivity of Al substrate prepared by the anodizing will be studied. The optimum parameters to fabricate aluminum heat-dissipation substrates for high power LED will be obtained. By reducing the thermal conductivity of insulation layer and decreasing the number of heat sink in internal substrate, this method leads the thermal resistance to a minimum. This new structure of package can improve the heat dissipation effectively. The techniques can eliminate lamination between metal layer and insulating layer on high temperation, and can solve the question about traditional IMS techniques.

LED照明是当今科技的研究热点之一。随着LED发光效率的不断提高，LED 驱动电流的大幅度增加，散热问题己经成为大功率LED商品化的最大障碍。散热不解决会影响到LED的光输出特性和器件的寿命，是大功率LED封装中的关键问题。在本项目中我们提出了一种在铝质基板上直接制备氧化铝绝缘层，再在绝缘层上溅射镀覆导电薄膜来制备高导热覆铜基板的设计，通过对铝基板的电流密度、硫酸质量浓度、温度和时间等因素对其热阻、厚度、绝缘电阻率的影响，获得最优化参数，根据优化参数制备优良性能的阳极氧化铝基板，降低绝缘层导热系数，减少基板内部热沉数量，把热阻降到最低程度。此种散热封装结构能提高散热效果，该技术能消除高温下金属层和绝缘层的分层或剥离，还有效解决传统的IMS 技术所面临的问题。

LED照明是当今科技的研究热点之一。随着LED发光效率的不断提高，LED 驱动电流的大幅度增加，散热问题己经成为大功率LED商品化的最大障碍。散热不解决会影响到LED的光输出特性和器件的寿命，是大功率LED封装中的关键问题。为了提高功率型LED灯的散热效率，本项目对研制的铝基板进行了性能测试方法的研究。通过对常用的LED基板导热性能、绝缘性能以及金属电极膜层结合力测试方法进行对比研究，并选用了适合阳极氧化铝基板的测试方法对本课题自主研制的铝基板关键性能进行了测试评价，同时采用微弧氧化技术在铝合金基板上制备氧化物绝缘层，并采用磁控溅射工艺在其上制备了导电膜。通过研究不同电解液成分制备的铝基板，发现加入了KOH的Na2SiO3溶液制备的膜层具有最佳的绝缘性能。还对磁控溅射工艺对导电膜层结合力的影响进行了研究，得到了针对Cr/Ni-Cu金属膜层的最佳镀膜工艺。依照此工艺镀制的金属化膜层结合力可达6.4Mpa。。结果表明：测试方法合理，基板的导热性能、绝缘性能以及金属电极膜层结合力满足使用要求。