Study on melting process controlling method of fine pitch solder joints by laser heating

In order to develop a no solder bridging assembly method for high density electronic devices, temperature distribution of joints of fine pitch QFP device is simulated under laser single point and laser scanning. Then the experiments of QFP256 device assembly are performed under heating condition of infrared furnace and laser scanning. Simulation results show that temperature distribution in fine pitch joints is controlled by laser local heating characteristics, and then melting range of solder on the joint is controlled for defense solder bridging on adjacent leads. Experimental results show that suitable laser heating can carry out no bridging assembly for fine pitch devices.