Development of laser soldering process for a tape carrier package

A novel laser soldering process for bonding high lead count packages such as TCPs (tape carrier packages) to PWBs (printed wiring boards) in a short time and for excellent bonding quality has been developed. This technique is designed for outer lead bonding of the TCP with high lead counts using a YAG laser beam. The new laser soldering process is superior in quality without causing damage to the package and the PWB, because only a pair of single lead and pad is irradiated with the laser beam in a short time (10 ms). By scanning the laser beam from the pad tip to the lead root, solder on the pad is melted and flowed effectively to form good joints. This method results in the adequate length of the bonded area. The beam scan resting method for 2 ms at the tip of the pad is advantageous for forming good joints