Method of marking a thin film package

The disclosure describes a method of manufacturing a structure of a thin, flexible package assembly that permits electrical devices to be bonded to an electrical circuit utilizing mixed bonding techniques. A sacrificial metal carrier material is used to support a thin polyimide or TEFLON substrate, through which openings, called "vias", are formed at locations where bonding pad areas are needed to affix electrical devices. An electrical circuit is formed on the thin flexible substrate, including making the vias conductive, utilizing known processes, and then, the sacrificial metal carrier material is removed, as for example by etching it away, except in locations where metal bumps will be needed to bone a device by thermo compression bonding.