Abstract: A die-mounting substrate and method incorporating dummy traces for improving mounting film planarity makes the use of film attach possible with a simplified manufacturing process and in applications where film-attach was not previously practical. The die-mounting substrate includes dummy traces that are generated along with signal traces extending into the die mounting area of the substrate. The dummy traces are designed according to the same design rules as the signal traces and are disposed in otherwise empty regions between signal traces and vias within the die mounting area. The result is die mounting area without regions empty of signal traces that previously either lack conductor or are filled completely with conductor, either of which will result in surface variation that compromises the film bond.