TITLE OF THE INVENTION A bonding tool A bonding tool for TAB, used in the production of semiconductor chips, which is provided with, at the end thereof, a substrate consisting of a member selected from the group consisting of sintered compacts of Si or Si3N4 as a predominant component, sintered compacts of SiC as a predominant component, sintered compacts of AlN as a predominant component and composite compacts thereof, the substrate being coated with polycrystalline diamond deposited by gaseous phase synthesis method.