Abstract: Method of fabricating high density multilayer interconnect structures or flexible HDMI decals. The methods secure a top surface of an HDMI decal fabricated on a rigid substrate to a protective film layer which is in turn adhesively secured to a flat carrier. This structure is then demounted or delaminated from the rigid substrate. The bottom of the HDMI decal, with the protective film layer and flat carrier attached thereto, is secured to a mounting substrate using a relatively thick adhesive layer. After the HDMI decal is adhesively secured to the mounting substrate, the carrier and protective film layer are removed. The top surface of the HDMI decal thus remains flat after it is secured to the mounting substrate, and therefore connection of integrated circuit chips to contact pads on the top surface of the decal is ensured because this surface is flat. The carrier and protective film layer also protects the top surface of the decal while it is secured to the mounting substrate.

Abstract: Methods of producing a chip scale package that enables any chip with peripheral bond pads to be converted to an area array chip scale package suitable for chip on board assembly. The present invention produces the equivalent of a flip chip die when a chip supplier does not provide one. Processing is performed that provides thin film metal interconnections between the chip bond pads and area array bond pads on the bottom of the package. High reliability thin film metal interconnections are thus provided that connect the bond pads of the chip to the area array bond pads to permit external connection to the chip.

Abstract: Methods of forming two-sided high density multilayer interconnect (HDMI) structures on a relatively large carrier and subsequently releasing and removing one or more structures to provide useable flexible interconnects or decals. In general, a carrier is provided and a release layer is formed on the carrier. Flexible high density multilayer interconnect structures are fabricated on the release layer. The release layer is processed to release and remove one or more flexible HDMI structures from the carrier. The carrier may be an ultraviolet transparent substrate, such as quartz, for example, and the release layer may be a polyimide layer. The HDMI structures are released by irradiating the release layer through the transparent carrier using ultraviolet radiation from an ultraviolet radiation source. Alternatively, a silicon carrier may be used that has a metal or silicon dioxide release layer formed thereon.