A new golden bump making method for high power LED flip chip

摘要

Nowadays, high power LED is often packaged with flip chip method. The gold bump is usually made by electroplating or gold evaporation, which cause the environment pollution and material waste. A gold wire bump manufacture technology for high power LED flip chip is described in this paper. The wire bond device is used and different bump making parameters, such as weld temperature, pressure and ultrasonic power, are optimized through experiments. At the same time, a new bump wire tail height managing process is introduced. The gold wire bump with this method height difference keep in 3 micrometers and which is convenient for flip chip. Then, rapid annealing is taken to make sure the gold wire bump has a well adherence to the wafer. At last, the bump weld result is tested and the bump invalidation is analyzed with the SEM. The bonding force between bump and wafer more than 10 grams. The flip chip high power LED with gold wire bump has low forth voltage and heat resistance. All of above proved that the gold wire bump is convenient and reliable for high power flip chip LED.