Tool and method for welding to IC frames

This invention relates to manufacturing integrated circuits and particularly to a tool and method for butt welding a wire to an integrated circuit frame. A device for forming an encapsulated end of a wire bonded to a metal surface. The device includes a clamp being an end surface of a bar is pressed against a surface of a plate. The end surface has a ridge formed around its edge. Therefore, when a clamping force is applied to the bar against the plate, the metal sheet clamped between the plate surface and end surface of the bar, the clamping force is concentrated at an interface between the metal surface and ridge. When encapsulate is injected into the contact region, the ridge prevents contaminating material from migrating over interface between bar and plate where the welding step is to be performed. The bar is then withdrawn leaving a tunnel through which the wire is positioned with the end of the wire in contact bondable to the clean surface of metal. The wire is positioned in the tunnel and bonded to the metal surface.