Strip-shaped composite material for probe needles
A strip-shaped sandwich composite material for producing probe needles, wherein an inner core layer is arranged between two outer cover layers, wherein the inner core layer consists of a palladium alloy comprising at least 30 wt. % palladium or of a platinum alloy comprising at least 30 wt. % platinum, and wherein the two outer cover layers consist of a precipitation-hardened and/or dispersion-hardened copper alloy comprising at least 90 wt. % copper and/or silver alloy comprising at least 70 wt. % silver. The invention also relates to a probe needle, a bonding strip, a probe needle array and a method for producing a composite material.
1 . A composite material for producing probe needles for electronic testing of semiconductor elements, wherein the composite material is strip-shaped and is delimited by two mutually parallel main surfaces, wherein the composite material is layered perpendicularly to the parallel main surfaces and has a sandwich construction comprising an inner core layer and two outer cover layers, wherein the inner core layer is arranged between the two outer cover layers, and the inner core layer is firmly connected on two opposite sides to the two outer cover layers, wherein the two outer cover layers form the parallel main surfaces, wherein the inner core layer consists of a palladium alloy comprising at least 30 wt. % palladium or of a platinum alloy comprising at least 30 wt. % platinum, and wherein the two outer cover layers consist of a precipitation-hardened and/or dispersion-hardened copper alloy comprising at least 90 wt. % copper, or of a precipitation-hardened and/or dispersion-hardened silver alloy comprising at least 70 wt. % silver, or of a precipitation-hardened and/or dispersion-hardened copper alloy comprising at least 90 wt. % copper and of a precipitation-hardened and/or dispersion-hardened silver alloy comprising at least 70 wt. % silver.
2 . The composite material according to claim 1 , wherein the inner core layer is directly connected to the two outer cover layers, and/or the composite material consists of the inner core layer and the outer cover layers.
3 . The composite material according to claim 1 , wherein the two outer cover layers consist of a precipitation-hardened and/or dispersion-hardened copper alloy comprising at least 90 wt. % copper.
4 . The composite material according to claim 1 , wherein
the inner core layer consists of a palladium alloy containing at least 30 wt. % palladium.
5 . The composite material according to claim 1 , wherein
the composite material has an electrical conductivity, measured by means of a four-point measurement method at room temperature, on one of the two outer cover layers, of at least 35% IACS (20.3 ×10 6 S/m), and/or
the composite material has a Vickers hardness HV0.05, at room temperature, in the two cover layers of at least 170, and/or
the composite material has a tensile strength at room temperature in parallel with the plane of the inner core layer of at least 1000 MPa, and/or
the composite material has a yield strength at room temperature in parallel with the plane of the inner core layer of at least 950 MPa.
6 . The composite material according to claim 1 , wherein
the precipitation-hardened and/or dispersion-hardened copper alloy is a precipitation-hardened and/or dispersion-hardened copper-chromium alloy comprising at least 98 wt. % copper, or
the precipitation-hardened and/or dispersion-hardened copper alloy is a precipitation-hardened copper-chromium-titanium alloy comprising at least 99 wt. % copper, or
the precipitation-hardened and/or dispersion-hardened copper alloy is a precipitation-hardened copper-chromium-silver alloy comprising at least 98 wt. % copper, or
the precipitation-hardened and/or dispersion-hardened copper alloy is a precipitation-hardened and/or dispersion-hardened copper-silver alloy comprising at least 90 wt. % copper, and/or
the precipitation-hardened and/or dispersion-hardened silver alloy is a silver-copper alloy comprising at least 70 wt. % silver, and/or
the palladium alloy is a palladium-copper-silver alloy comprising palladium as the main component, wherein the palladium-copper-silver alloy has a weight ratio of palladium to copper of at least 1.05 and at most 1.6, and a weight ratio of palladium to silver of at least 3 and at most 6, and wherein the palladium-copper-silver alloy contains more than 1 wt. % and up to at most 6 wt. % ruthenium, rhodium or ruthenium and rhodium, and, as the remainder, palladium, copper and silver and at most 1 wt. % other metal elements, including impurities, or
the palladium alloy is a palladium-silver-copper-platinum alloy or a palladium-silver-copper-platinum-gold-zinc, or
the palladium alloy is a palladium-copper-silver-ruthenium alloy, or
the palladium alloy is a palladium-copper-silver-rhodium alloy, or
the palladium alloy is a palladium-copper-silver alloy, or
the palladium alloy is a palladium-silver-copper alloy, or
the platinum alloy is a platinum-nickel alloy.
7 . The composite material according to claim 1 , wherein
the precipitation-hardened and/or dispersion-hardened copper alloy comprises up to 2 wt. % precipitates and/or dispersoids, the precipitates and/or dispersoids consisting to at least 95 wt. % of at least one of the elements selected from the list consisting of chromium, titanium, silicon, iron, oxygen, zirconium and silver.
8 . The composite material according to claim 1 , wherein
the inner core layer consists of a precipitation-hardened and/or dispersion-hardened palladium alloy, or of a precipitation-hardened and/or dispersion-hardened platinum alloy.
9 . A probe needle or bonding strip consisting of a strip of a composite material according to claim 1 .
10 . The probe needle according to claim 9 , wherein the probe needle has a tip that consists of a same material of the inner core layer.
11 . A probe needle array having a plurality of probe needles according to claim 9 arranged next to one another.
12 . A method for producing a composite material made of two metal alloys, wherein the composite material is suitable and provided for the production of probe needles for the electronic testing of semiconductor elements and wherein the method is characterized by the following chronologically successive steps:
A) providing a first strip of a palladium alloy comprising at least 30 wt. % palladium or of a platinum alloy comprising at least 30 wt. % platinum, and a second strip of a precipitation-hardened and/or dispersion-hardened copper alloy comprising at least 90 wt. % copper or of a precipitation-hardened and/or dispersion-hardened silver alloy comprising at least 70 wt. % silver, and a third strip of a precipitation-hardened and/or dispersion-hardened copper alloy comprising at least 90 wt. % copper, or of a precipitation-hardened and/or dispersion-hardened silver alloy comprising at least 70 wt. % silver,
B) arranging the first strip between the second strip and the third strip, and placing the first strip against the second strip and against the third strip, and
C) connecting the first strip to the second strip and the third strip by roll bonding the strips placed against one another, the roll bonding producing a continuous strip-shaped composite material from the materials of the first strip, the second strip and the third strip.
13 . The method according to claim 12 , wherein
after step C), a step D) is performed:
D) temperature treatment of the composite produced in step C), the material of the first strip being precipitation-hardened and/or dispersion-hardened during the temperature treatment.
14 . The method according to claim 12 , wherein
a composite material is produced by means of the method, or at least one probe needle or at least one bonding strip is produced by cutting or punching the composite material, preferably a plurality of probe needles or bonding strips produced by means of the method, by cutting or punching.
15 . The composite material according to claim 1 , wherein the two outer cover layers consist of a precipitation-hardened and/or dispersion-hardened copper alloy comprising at least 97 wt. % copper.
16 . The composite material according to claim 1 , wherein the inner core layer consists of a palladium alloy containing at least 35 wt. % palladium.
17 . The composite material according to claim 1 , wherein the precipitation-hardened and/or dispersion-hardened copper alloy comprises up to 1 wt. % precipitates and/or dispersoids, the precipitates and/or dispersoids consisting to at least 95 wt. % of at least one of the elements selected from the list consisting of chromium, titanium, silicon, iron, oxygen, zirconium and silver.
18 . The composite material according to claim 1 , wherein the composite material has an electrical conductivity, measured by means of a four-point measurement method at room temperature, on one of the two outer cover layers, of at least 40% IACS (23.2 ×10 6 S/m).
19 . The composite material according to claim 1 , wherein
the composite material has a Vickers hardness HV0.05, at room temperature, in the two cover layers of at least 190, and/or
the composite material has a tensile strength at room temperature in parallel with the plane of the inner core layer of at least 1100 MPa, and/or
the composite material has a yield strength at room temperature in parallel with the plane of the inner core layer of at least 1050 MPa.