Method of patterned metal reflow on interconnect substrates

Claim 1

A method of electrically connecting a pair of spaced electrical contacts on a surface of a substrate, comprising: coating a linking metal over a first electrical contact without forming a continuous path of linking metal between the first electrical contact and a second electrical contact; deposing a wetting metal on the surface to form a continuous path of wetting metal between the contacts; heating the substrate to at least the melting point of the linking metal so that the linking metal melts and reflows across the wetting metal to form a continuous path of linking metal corresponding to the continuous wetting metal path between the contacts; and cooling the substrate so that the linking metal solidifies in the continuous linking metal path, bonds to the wetting metal and the contacts, and forms an electrically conductive link between the contacts.

Claim 2

A method of electrically connecting a pair of spaced electrical contacts on a surface of a substrate, comprising: coating a linking metal over a first electrical contact without forming a continuous path of linking metal between the first electrical contact and a second electrical contact; deposing a wetting metal on the surface to form a continuous path of wetting metal between the contacts; heating the substrate to at least the melting point of the linking metal so that the linking metal melts and reflows across the wetting metal to form a continuous path of linking metal corresponding to the continuous wetting metal path between the contacts; and cooling the substrate so that the linking metal solidifies in the continuous linking metal path, bonds to the wetting metal and the contacts, and forms an electrically conductive link between the contacts.

Claim 15

A method of reflowing linking metal between first and second spaced electrical contacts which extend above the top surface of a dielectric substrate, comprising: coating a linking metal over the first and second contacts without depositing a continuous path of the linking metal therebetween; depositing a wetting metal on the surface in a continuous path between the first and second contacts; heating the substrate to at least the melting point of the linking metal so that the linking metal melts, reflows across the wetting metal and connects the first and second contacts; and cooling the substrate so that the linking metal solidifies, bonds to the wetting metal and the contacts but not the surface, and forms an electrically conductive link between the contacts which corresponds to the continuous path of the wetting metal.

Claim 16

A method of reflowing linking metal between first and second spaced electrical contacts which extend above the top surface of a dielectric substrate, comprising: coating a linking metal over the first and second contacts without depositing a continuous path of the linking metal therebetween; depositing a wetting metal on the surface in a continuous path between the first and second contacts; heating the substrate to at least the melting point of the linking metal so that the linking metal melts, reflows across the wetting metal and connects the first and second contacts; and cooling the substrate so that the linking metal solidifies, bonds to the wetting metal and the contacts but not the surface, and forms an electrically conductive link between the contacts which corresponds to the continuous path of the wetting metal.

Claim 17

A method for providing patterned metal reflow on a substrate, comprising: coating a linking metal over a plurality of spaced electrical contact pads extending above a top dielectric surface on the substrate without depositing the linking metal on the dielectric; selectively depositing a wetting metal on the top dielectric surface to form continuous wetting metal paths between certain pairs of pads; and then heating the substrate to at least the melting point of the linking metal so that the linking metal melts, reflows across the wetting metal, and forms a metal link on the wetting metal between said certain pairs of pads, thereby providing a well-adhering reflowed metallization pattern corresponding to the continuous wetting metal paths between said certain pairs of pads.

Claim 18

A method for providing patterned metal reflow on a substrate, comprising: coating a linking metal over a plurality of spaced electrical contact pads extending above a top dielectric surface on the substrate without depositing the linking metal on the dielectric; selectively depositing a wetting metal on the top dielectric surface to form continuous wetting metal paths between certain pairs of pads; and then heating the substrate to at least the melting point of the linking metal so that the linking metal melts, reflows across the wetting metal, and forms a metal link on the wetting metal between said certain pairs of pads, thereby providing a well-adhering reflowed metallization pattern corresponding to the continuous wetting metal paths between said certain pairs of pads.

Claim 19

A method of selectively interconnecting a plurality of spaced electrical contact pads extending above a top planar surface on a customizable substrate, comprising: coating a linking metal over the pads without depositing the linking metal on the surface; selectively depositing a wetting metal on the surface without depositing the wetting metal over the pads to form a continuous path between the pads; heating the entire substrate to at least the melting point of the linking metal so that the linking metal melts and reflows across the wetting metal; and cooling the substrate so that the reflowed wetting metal forms a solid metal link bonded to the wetting metal and the pads but not the surface, thereby customizing the substrate.

Claim 20

A method of selectively interconnecting a plurality of spaced electrical contact pads extending above a top planar surface on a customizable substrate, comprising: coating a linking metal over the pads without depositing the linking metal on the surface; selectively depositing a wetting metal on the surface without depositing the wetting metal over the pads to form a continuous path between the pads; heating the entire substrate to at least the melting point of the linking metal so that the linking metal melts and reflows across the wetting metal; and cooling the substrate so that the reflowed wetting metal forms a solid metal link bonded to the wetting metal and the pads but not the surface, thereby customizing the substrate.

Claim 21

The method of claims 16 wherein the substrate is not heated to a sufficiently high temperature to melt copper.

Claim 22

The method of claims 16 wherein the wetting metal is selected from the group consisting of silver, gold, copper, nickel, lead, palladium, cobalt indium, platinum, rhenium, osmium and tin.

Claim 30

A method for providing patterned metal reflow on a substrate, comprising: coating a linking metal selected from the group consisting of tin, indium, tin/lead alloy, gold/tin alloy, tin/cadmium alloy, tin/silver alloy, tin/lead/silver alloy and tin/copper alloy over a plurality of spaced pads extending above the top surface of the substrate without depositing the linking metal on the surface; selectively depositing on the surface a wetting metal selected from the group consisting of silver, gold, copper, nickel, lead, palladium, cobalt indium, platinum, rhenium, osmium, and tin in a pattern controlled by a laser to form continuous paths between certain pairs of pads; heating the substrate to at least the melting point of the linking metal so that the linking metal melts and reflows across the wetting metal; and cooling the substrate below the melting point of the linking metal to form a solid metal link on the wetting metal between said certain pairs of pads, thereby providing a reflowed linking metallization pattern corresponding to the wetting metal paths between said certain pairs of pads.

Claim 31

A method for providing patterned metal reflow on a substrate, comprising: coating a linking metal selected from the group consisting of tin, indium, tin/lead alloy, gold/tin alloy, tin/cadmium alloy, tin/silver alloy, tin/lead/silver alloy and tin/copper alloy over a plurality of spaced pads extending above the top surface of the substrate without depositing the linking metal on the surface; selectively depositing on the surface a wetting metal selected from the group consisting of silver, gold, copper, nickel, lead, palladium, cobalt indium, platinum, rhenium, osmium, and tin in a pattern controlled by a laser to form continuous paths between certain pairs of pads; heating the substrate to at least the melting point of the linking metal so that the linking metal melts and reflows across the wetting metal; and cooling the substrate below the melting point of the linking metal to form a solid metal link on the wetting metal between said certain pairs of pads, thereby providing a reflowed linking metallization pattern corresponding to the wetting metal paths between said certain pairs of pads.

Claim 32

A method for providing patterned metal reflow on a substrate, comprising: coating a solder linking metal containing tin over a plurality of spaced adjacent copper pads extending above the top surface of the substrate without forming a continuous path of solder between any pads; selectively depositing on the surface a copper wetting metal at least one micron thick in a pattern controlled by a laser to form continuous paths between certain pairs of copper pads; heating the entire substrate to at least the melting point of the solder so that the solder melts and reflows across the copper wetting metal; and cooling the substrate to form a solid soldered link between said certain pairs of copper pads, thereby providing a reflowed solder pattern corresponding and bonded to the copper wetting metal paths between said certain pairs of copper pads.

Claim 33

A method for providing patterned metal reflow on a substrate, comprising: coating a solder linking metal containing tin over a plurality of spaced adjacent copper pads extending above the top surface of the substrate without forming a continuous path of solder between any pads; selectively depositing on the surface a copper wetting metal at least one micron thick in a pattern controlled by a laser to form continuous paths between certain pairs of copper pads; heating the entire substrate to at least the melting point of the solder so that the solder melts and reflows across the copper wetting metal; and cooling the substrate to form a solid soldered link between said certain pairs of copper pads, thereby providing a reflowed solder pattern corresponding and bonded to the copper wetting metal paths between said certain pairs of copper pads.

Claim 36

A method of electrically connecting a plurality of electrical contacts on a substrate, comprising the following steps in the sequence set forth: depositing a wetting metal on the substrate between first and second electrical contacts to form a continuous wetting metal path therebetween; depositing a linking metal over at least the first electrical contact without forming a continuous linking metal path between the first and second electrical contacts; and heating the substrate to at least the melting point of the linking metal so that the linking metal melts and reflows off the first electrical contact onto the wetting metal to form an electrically conductive link between the first and second electrical contacts in a pattern corresponding to the continuous wetting metal path therebetween.

Claim 37

A method of electrically connecting a plurality of electrical contacts on a substrate, comprising the following steps in the sequence set forth: depositing a wetting metal on the substrate between first and second electrical contacts to form a continuous wetting metal path therebetween; depositing a linking metal over at least the first electrical contact without forming a continuous linking metal path between the first and second electrical contacts; and heating the substrate to at least the melting point of the linking metal so that the linking metal melts and reflows off the first electrical contact onto the wetting metal to form an electrically conductive link between the first and second electrical contacts in a pattern corresponding to the continuous wetting metal path therebetween.

Claim 38

A method of electrically connecting a plurality of electrical contacts extending above a dielectric on a substrate, comprising the following steps in the sequence set forth: (1) depositing a wetting metal on the dielectric between first and second electrical contacts to form a continuous wetting metal path therebetween; (2) depositing a linking metal on the entire substrate; (3) heating the entire substrate to at least the melting point of the linking metal so that the linking metal melts and wets the wetting metal and the contacts but not the dielectric; (4) cooling the substrate so that the linking metal solidifies and adheres to the wetting metal and the electrical contacts but fails to adhere to the dielectric; and (5) removing the non-adhering linking metal from the substrate wherein the linking metal which remains on the substrate forms an electrically conductive link between the first and second electrical contacts in a pattern corresponding to the wetting metal.

Claim 39

A method of electrically connecting a plurality of electrical contacts extending above a dielectric on a substrate, comprising the following steps in the sequence set forth: (1) depositing a wetting metal on the dielectric between first and second electrical contacts to form a continuous wetting metal path therebetween; (2) depositing a linking metal on the entire substrate; (3) heating the entire substrate to at least the melting point of the linking metal so that the linking metal melts and wets the wetting metal and the contacts but not the dielectric; (4) cooling the substrate so that the linking metal solidifies and adheres to the wetting metal and the electrical contacts but fails to adhere to the dielectric; and (5) removing the non-adhering linking metal from the substrate wherein the linking metal which remains on the substrate forms an electrically conductive link between the first and second electrical contacts in a pattern corresponding to the wetting metal.

Claim 41

A method of electrically connecting a plurality of electrical contacts extending above a dielectric surface on a substrate, comprising the following steps in the sequence set forth: (1) depositing a wetting metal on the surface between first and second electrical contacts to form a continuous wetting metal path therebetween; (2) depositing a linking metal over the entire surface of the substrate; (3) heating the entire substrate to at least the melting point of the linking metal so that the linking metal melts and wets the wetting metal and the electrical contacts but fails to wet the surface; (4) cooling the substrate so that the linking metal solidifies and adheres to the wetting metal and the electrical contacts but fails to adhere to the surface; and (5) removing any linking metal in contact with the dielectric but not in contact with the wetting metal or the electrical contacts, wherein the linking metal remaining on the substrate forms an electrically conductive link between the first and second electrical contacts in a pattern corresponding to the continuous wetting metal path.

Claim 42

A method of electrically connecting a plurality of electrical contacts extending above a dielectric surface on a substrate, comprising the following steps in the sequence set forth: (1) depositing a wetting metal on the surface between first and second electrical contacts to form a continuous wetting metal path therebetween; (2) depositing a linking metal over the entire surface of the substrate; (3) heating the entire substrate to at least the melting point of the linking metal so that the linking metal melts and wets the wetting metal and the electrical contacts but fails to wet the surface; (4) cooling the substrate so that the linking metal solidifies and adheres to the wetting metal and the electrical contacts but fails to adhere to the surface; and (5) removing any linking metal in contact with the dielectric but not in contact with the wetting metal or the electrical contacts, wherein the linking metal remaining on the substrate forms an electrically conductive link between the first and second electrical contacts in a pattern corresponding to the continuous wetting metal path.