大功率白光LED低热阻封装技术研究-精微制造工程专业论文.docx

Abstract Light emitting diode(LED) is a kind of semiconductor optical components which has been used as indicator lights over a very long period in the past. With the successful fabrication of power LED chip and the increasing luminous efficacy recently, general lighting using LEDs becomes feasible. Semiconductor lighting is considered a revolution in the area of illumination in the 21st century, LED applications in general lighting are being given more and more attention by both the semiconductor sector and illumination sector. With the input power for LED chip becoming higher and higher, there is a severe challenge to the packaging technology. In order to make LED lighting have a bigger market in the general lighting area, we have to resolve the heat-dissipating problem which is caused by increasing input power properly, and to choose proper packaging materials and packaging structures to reduce thermal resistance in packaging. In this thesis, low thermal resistance packaging technology of White High-Power LEDs is studied. Firstly, the advantages and feasibility of LED lighting is introduced, the developments and prospects of LED applications, as well as the critical problems of LED application in general lighting are analyzed. Secondly, the structure and luminous principle of high power LED chip are introduced, the mechanism how the heat is generated from internal LED chip and the influence of the junction temperature on the performance of LED device are introduced as well. The international main-stream techniques of white LED chip packaging are presented. The thesis also establishes the model of thermal resistance for LED packaging and has found the major approaches to reducing junction temperature. Thirdly, the paper discusses how to choose packaging materials and packaging structures which play a very important role in thermal resistance of LED packaging. Especially DBC (direct bonded copper) ceramic substrate, which is designed by ourselves is analyzed and t