A palladium-coated copper bonding wire includes: a core material containing copper as a main component; and a palladium layer on the core material, in which a concentration of palladium relative to the entire wire is 1.0 mass % or more and 4.0 mass % or less, and a work hardening coefficient in an amount of change of an elongation rate 2% or more and a maximum elongation rate εmax % or less of the wire, is 0.20 or less.

The bonding wire being a Pd-coated copper bonding wire includes: a copper core material; and a Pd layer and containing a sulfur group element, in which with respect to the total of copper, Pd, and the sulfur group element, a concentration of Pd is 1.0 mass % to 4.0 mass % and a total concentration of the sulfur group element is 50 mass ppm or less, and a concentration of S is 5 mass ppm to 2 mass ppm, a concentration of Se is 5 mass ppm to 20 mass ppm, or a concentration of Te is 15 mass ppm to 50 mass ppm or less. A wire bonding structure includes a Pd-concentrated region with the concentration of Pd being 2.0 mass % or more relative to the total of Al, copper, and Pd near a bonding surface of an Al-containing electrode of a semiconductor chip and a ball bonding portion.

A process for electrically connecting contact surfaces of electronic components by capillary wedge bonding a round wire of 8 to 80 μm to the contact surface of a first electronic component, forming a wire loop, and stitch bonding the wire to the contact surface of a second electronic component, wherein the wire comprises a wire core having a silver or silver-based wire core with a double-layered coating comprised of a 1 to 50 nm thick inner layer of nickel or palladium and an adjacent 5 to 200 nm thick outer layer of gold.

There is provided a palladium-coated copper bonding wire that does not cause a shrinkage cavity during first bonding, has high bonding reliability, and is capable of maintaining excellent bonding reliability for a long period of time even in high-temperature and high-humidity environments. A palladium-coated copper bonding wire in which a concentration of palladium is 1.0 mass % or more and 4.0 mass % or less relative to the total of copper, palladium, and a sulfur group element, a total concentration of the sulfur group element is 50 mass ppm or less, and a concentration of sulfur is 5 mass ppm or more and 12 mass ppm or less, a concentration of selenium is 5 mass ppm or more and 20 mass ppm or less, or a concentration of tellurium is 15 mass ppm or more and 50 mass ppm or less, and the palladium-coated copper bonding wire including a palladium-concentrated region with the average concentration of palladium of 6.5 atom % or more and 30.0 atom % or less relative to the total of copper and palladium within a range from a surface of a tip portion of a free air ball formed at a tip of the wire to 5.0 nm or more and 100.0 nm or less.

There is provided a palladium-coated copper bonding wire that does not cause a shrinkage cavity during first bonding, has high bonding reliability, and is capable of maintaining excellent bonding reliability for a long period of time even in high-temperature and high-humidity environments. A palladium-coated copper bonding wire in which a concentration of palladium is 1.0 mass % or more and 4.0 mass % or less relative to the total of copper, palladium, and a sulfur group element, a total concentration of the sulfur group element is 50 mass ppm or less, and a concentration of sulfur is 5 mass ppm or more and 12 mass ppm or less, a concentration of selenium is 5 mass ppm or more and 20 mass ppm or less, or a concentration of tellurium is 15 mass ppm or more and 50 mass ppm or less, and the palladium-coated copper bonding wire including a palladium-concentrated region with the average concentration of palladium of 6.5 atom % or more and 30.0 atom % or less relative to the total of copper and palladium within a range from a surface of a tip portion of a free air ball formed at a tip of the wire to 5.0 nm or more and 100.0 nm or less.

A wire comprising a wire core with a surface, the wire core having a coating layer superimposed on its surface, wherein the wire core itself consists of: (a) pure silver consisting of (a1) silver in an amount in the range of from 99.99 to 100 wt.-% and (a2) further components in a total amount of from 0 to 100 wt.-ppm or (b) doped silver consisting of (b1) silver in an amount in the range of from >99.49 to 99.997 wt.-%, (b2) at least one doping element selected from the group consisting of calcium, nickel, platinum, palladium, gold, copper, rhodium and ruthenium in a total amount of from 30 to <5000 wt.-ppm and (b3) further components in a total amount of from 0 to 100 wt.-ppm, or (c) a silver alloy consisting of (c1) silver in an amount in the range of from 89.99 to 99.5 wt.-%, (c2) at least one alloying element selected from the group consisting of nickel, platinum, palladium, gold, copper, rhodium and ruthenium in a total amount in the range of from 0.5 to 10 wt.-% and (c3) further components in a total amount of from 0 to 100 wt.-ppm, or (d) a doped silver alloy consisting of (d1) silver in an amount in the range of from >89.49 to 99.497 wt.-%, (d2) at least one doping element selected from the group consisting of calcium, nickel, platinum, palladium, gold, copper, rhodium and ruthenium in a total amount of from 30 to <5000 wt.-ppm, (d3) at least one alloying element selected from the group consisting of nickel, platinum, palladium, gold, copper, rhodium and ruthenium in a total amount in the range of from 0.5 to 10 wt.-% and (d4) further components in a total amount of from 0 to 100 wt.-ppm, wherein the at least one doping element (d2) is other than the at least one alloying element (d3), wherein the individual amount of any further component is less than 30 wt.-ppm, wherein the individual amount of any doping element is at least 30 wt.-ppm, wherein all amounts in wt.-% and wt.-ppm are based on the total weight of the core, and wherein the coating layer is a double-layer comprised of a 1 to 1000 nm inner layer of gold and an adjacent 0.5 to 100 nm thick outer layer of palladium or a double-layer comprised of a 0.5 to 100 nm thick inner layer of palladium and an adjacent >200 to 1000 nm thick outer layer of gold.

A wire comprising a wire core with a surface, the wire core having a coating layer superimposed on its surface, wherein the wire core itself consists of: (a) pure silver consisting of (a1) silver in an amount in the range of from 99.99 to 100 wt.-% and (a2) further components in a total amount of from 0 to 100 wt.-ppm or (b) doped silver consisting of (b1) silver in an amount in the range of from >99.49 to 99.997 wt.-%, (b2) at least one doping element selected from the group consisting of calcium, nickel, platinum, palladium, gold, copper, rhodium and ruthenium in a total amount of from 30 to <5000 wt.-ppm and (b3) further components in a total amount of from 0 to 100 wt.-ppm, or (c) a silver alloy consisting of (c1) silver in an amount in the range of from 89.99 to 99.5 wt.-%, (c2) at least one alloying element selected from the group consisting of nickel, platinum, palladium, gold, copper, rhodium and ruthenium in a total amount in the range of from 0.5 to 10 wt.-% and (c3) further components in a total amount of from 0 to 100 wt.-ppm, or (d) a doped silver alloy consisting of (d1) silver in an amount in the range of from >89.49 to 99.497 wt.-%, (d2) at least one doping element selected from the group consisting of calcium, nickel, platinum, palladium, gold, copper, rhodium and ruthenium in a total amount of from 30 to <5000 wt.-ppm, (d3) at least one alloying element selected from the group consisting of nickel, platinum, palladium, gold, copper, rhodium and ruthenium in a total amount in the range of from 0.5 to 10 wt.-% and (d4) further components in a total amount of from 0 to 100 wt.-ppm, wherein the at least one doping element (d2) is other than the at least one alloying element (d3), wherein the individual amount of any further component is less than 30 wt.-ppm, wherein the individual amount of any doping element is at least 30 wt.-ppm, wherein all amounts in wt.-% and wt.-ppm are based on the total weight of the core, and wherein the coating layer is a double-layer comprised of a 1 to 1000 nm inner layer of gold and an adjacent 0.5 to 100 nm thick outer layer of palladium or a double-layer comprised of a 0.5 to 100 nm thick inner layer of palladium and an adjacent >200 to 1000 nm thick outer layer of gold.

A method of forming an electrical contact and a method of forming a chip package are provided. The methods may include arranging a metal contact structure including a non-noble metal and electrically contacting the chip, arranging a packaging material, and a protective layer including or essentially consisting of a portion formed at an interface between a portion of the metal contact structure and the packaging material, wherein the protective layer may include a noble metal, wherein the portion of the protective layer may include a plurality of regions free from the noble metal, and wherein the regions free from the noble metal may provide an interface between the packaging material and the non-noble metal of the metal contact structure.

A method of forming an electrical contact and a method of forming a chip package are provided. The methods may include arranging a metal contact structure including a non-noble metal and electrically contacting the chip, arranging a packaging material, and a protective layer including or essentially consisting of a portion formed at an interface between a portion of the metal contact structure and the packaging material, wherein the protective layer may include a noble metal, wherein the portion of the protective layer may include a plurality of regions free from the noble metal, and wherein the regions free from the noble metal may provide an interface between the packaging material and the non-noble metal of the metal contact structure.

In various embodiments, a method of forming an electrical contact is provided. The method may include depositing, by atomic layer deposition, a passivation layer over at least a region of a metal surface, wherein the passivation layer may include aluminum oxide, and electrically contacting the region of the metal surface with a metal contact structure, wherein the metal contact structure may include copper.