A system has been developed for implementing a solderless fine pitch Tape Automated Bonding (TAB) process. The process was applied to multichip module (MCM) packages with lead pitch of 100 mum. The technology can be extended to ultrafine pitch as low as 25 mum and can be used for both inner lead bonding and outer lead bonding. The technology is based on metal to metal diffusion at the lead to pad interface using a "hot" tip energized by a laser. A closed end flat tip was used to comply with safety requirements and provide uniform temperature distribution across the footprint of the tip. The tip has shown no degradation during the initial testing of 25 000 bonds. The technology is much simpler compared to the solder based TAB process. It is easily controlled, does not require any pretreatment of the pads and is less sensitive to pad contamination and surface nonplanarity. It can be applied to various sets of pad-lead metallurgies such as Au-Au, Au-Sn, Cu-Au, and Ni-Au. The study shows that the process can be designed to be reworkable which makes it suitable for MCM applications.