Abstract: Annealed copper foil (12) is coated with chromium film (16), followed by coating with an appropriate thickness of gold film (14) and is thermocompression bonded to an aluminum metallized substrate (18) on a silicon chip (30) to provide solderable, high current contacts to the chip. The foil is formed into appropriate electrical network-contact patterns (40) and is bonded to the silicon chip only where aluminum metallization exists on the chip. Leaf (wing) portions (46) of the foil extend beyond the boundaries of the silicon chip for subsequent retroflexing over the foil to provide electrical contact at predesignated locations (49). External contacts to the foil are made by penetrating through a ceramic lid positioned directly above the foil area. Thus, direct thermocompression bonding of a principally copper foil to aluminum semiconductor pads can replace current gold detent/bump connections by securing a copper conductor to a silicon chip through an intermetallic AuAl.sub.2 link and an aluminum stratum.

Abstract: Annealed copper foil (12) is coated with chromium film (16), followed by coating with an appropriate thickness of gold film (14) and is thermocompression bonded to an aluminum metallized substrate (18) on a silicon chip (30) to provide solderable, high current contacts to the chip. The foil is formed into appropriate electrical network-contact patterns (40) and is bonded to the silicon chip only where aluminum metallization exists on the chip. Leaf (wing) portions (46) of the foil extend beyond the boundaries of the silicon chip for subsequent retroflexing over the foil to provide electrical contact at predesignated locations (49). External contacts to the foil are made by penetrating through a ceramic lid positioned directly above the foil area. Thus, direct thermocompression bonding of a principally copper foil to aluminum semiconductor pads can replace current gold detent/bump connections by securing a copper conductor to a silicon chip through an intermetallic AuAl.sub.2 link and an aluminum stratum.

Abstract: Annealed copper foil (12) is coated with chromium film (16), followed by coating with an appropriate thickness of gold film (14) and is thermocompression bonded to an aluminum metallized substrate (18) on a silicon chip (30) to provide solderable, high current contacts to the chip. The foil is formed into appropriate electrical network-contact patterns (40) and is bonded to the silicon chip only where aluminum metallization exists on the chip. Leaf (wing) portions (46) of the foil extend beyond the boundaries of the silicon chip for subsequent retroflexing over the foil to provide electrical contact at predesignated locations (49). External contacts to the foil are made by penetrating through a ceramic lid positioned directly above the foil area. Thus, direct thermocompression bonding of a principally copper foil to aluminum semiconductor pads can replace current gold detent/bump connections by securing a copper conductor to a silicon chip through an intermetallic AuAl.sub.2 link and an aluminum stratum.

Abstract: A method for producing a hole in a polymer film includes the steps of depositing a conductive layer onto the polymer film and irradiating a spot on the layer with a burst of focused laser energy at a level sufficient to form an opening in the film and, subsequently, plasma etching the film so as to form a hole of desired depth in the polymer film underlying the opening in the conductive layer. This method is particularly applicable to the formation of multichip intergrated circuit packages in which a plurality of chips formed in a semiconductor wafer are coated with a polymer film covering the chips and the substrates. The holes are provided for the purpose of interconnecting selected chip contact pads via a deposited conductive layer which overlies the film and fills the holes.