A method is disclosed for packaging semiconductor chips on a flexible substrate employing thin film transfer. The semiconductor chips are placed on a temporary adhesive substrate, then covered by a permanent flexible substrate with a casting layer for planarizingly embedding the chips on the permanent substrate before removing the temporary substrate. With the surface of the chips coplanar with the surface of the complete structure without any gaps, interconnect metal lines can be easily placed on the uninterrupted surface, connecting the chips and other components.