Method of fabrication of semiconductor device package

Claim 1

A method of electromechanically joining a plurality of spaced-apart terminal pads on an integrated circuit chip to a correspondingly positioned plurality of spaced-apart terminals pads on a substrate, wherein each of said terminal pads is composed of the same metal selected from the group consisting of gold, silver, and aluminum, said method comprising depositing a layer of insulative material over the surface of one of said chip and said substrate on which the respective terminal pads are located, opening windows in said insulative layer to expose a portion of each terminal pad which is to be electromechanically joined to a correspondingly positioned terminal pad on the other of said chip and said substrate, depositing an alloy of germanium and the metal of which each of said terminal pads is composed through said windows and into adherent contact with the respective exposed terminal pads, until said alloy forms a bump exceeding the thickness of said insulative layer and having a periphery overlying the edges of the insulative layer forming the respective window, said alloy capable of forming a melt upon heating to the eutectic temperature of germanium and said metal, inverting said one of said chip and said substrate on which the alloy bumps are fOrmed and bringing said bumps into engagement and registry with respective terminal pads on said other of said chip and said substrate so that each bump projects downwardly against a respective registered terminal pad, heating the alloy bumps to said eutectic temperature to produce a melt which flows away from said insulative layer and onto the respective underlying registered terminal pad, and cooling the melt to form a solid eutectic alloy bond between the terminals pads in registry on said chip and said substrate.

Claim 2

A method of electromechanically joining a plurality of spaced-apart terminal pads on an integrated circuit chip to a correspondingly positioned plurality of spaced-apart terminals pads on a substrate, wherein each of said terminal pads is composed of the same metal selected from the group consisting of gold, silver, and aluminum, said method comprising depositing a layer of insulative material over the surface of one of said chip and said substrate on which the respective terminal pads are located, opening windows in said insulative layer to expose a portion of each terminal pad which is to be electromechanically joined to a correspondingly positioned terminal pad on the other of said chip and said substrate, depositing an alloy of germanium and the metal of which each of said terminal pads is composed through said windows and into adherent contact with the respective exposed terminal pads, until said alloy forms a bump exceeding the thickness of said insulative layer and having a periphery overlying the edges of the insulative layer forming the respective window, said alloy capable of forming a melt upon heating to the eutectic temperature of germanium and said metal, inverting said one of said chip and said substrate on which the alloy bumps are fOrmed and bringing said bumps into engagement and registry with respective terminal pads on said other of said chip and said substrate so that each bump projects downwardly against a respective registered terminal pad, heating the alloy bumps to said eutectic temperature to produce a melt which flows away from said insulative layer and onto the respective underlying registered terminal pad, and cooling the melt to form a solid eutectic alloy bond between the terminals pads in registry on said chip and said substrate.

Claim 5

A method of producing a strong mechanical and electrical junction between an electrical contact pad on a planar surface of one body and an electrical contact pad on a planar surface of another body, wherein each of said contact pads is composed of the same metal selected from the group consisting of gold, silver, and aluminum, said method comprising forming a thin layer of dielectric material over the surface of one of said bodies including the surface of said contact pad thereon, etching an opening in said dielectric layer to expose the surface of the underlying contact pad, depositing an alloy of germanium and said metal on the exposed surface of said contact pad and over the surrounding edge of said dielectric layer to form a raised terminal region adherently bonded to the contact pad, said alloy capable of forming a melt upon heating to the eutectic temperature of germanium and said metal, positioning said bodies so that the raised terminal region projects downwardly from the contact pad to which it is adherently bonded and against the other contact pad, heating the raised terminal region to a temperature sufficient to form a molten eutectic composition of germanium and said metal and continuing said heating until said composition recedes from said dielectric layer and flows onto the surface of the underlying said other contact pad while maintaining contact with the surface of said contact pad to which the terminal region was initially bonded, and thereafter permitting the eutectic composition to cool to form a solid junction between the two contact pads.

Claim 6

A method of producing a strong mechanical and electrical junction between an electrical contact pad on a planar surface of one body and an electrical contact pad on a planar surface of another body, wherein each of said contact pads is composed of the same metal selected from the group consisting of gold, silver, and aluminum, said method comprising forming a thin layer of dielectric material over the surface of one of said bodies including the surface of said contact pad thereon, etching an opening in said dielectric layer to expose the surface of the underlying contact pad, depositing an alloy of germanium and said metal on the exposed surface of said contact pad and over the surrounding edge of said dielectric layer to form a raised terminal region adherently bonded to the contact pad, said alloy capable of forming a melt upon heating to the eutectic temperature of germanium and said metal, positioning said bodies so that the raised terminal region projects downwardly from the contact pad to which it is adherently bonded and against the other contact pad, heating the raised terminal region to a temperature sufficient to form a molten eutectic composition of germanium and said metal and continuing said heating until said composition recedes from said dielectric layer and flows onto the surface of the underlying said other contact pad while maintaining contact with the surface of said contact pad to which the terminal region was initially bonded, and thereafter permitting the eutectic composition to cool to form a solid junction between the two contact pads.