Method of forming surface protrusions on an article and the article with the protrusions attached
A method of forming surface protrusions on an article, and the article with the protrusions attached. The article may be an Integrated Circuit (IC) chip, a test probe for the IC chip or any suitable substrate or nanostructure. The surface protrusions are electroplated to a template or mold wafer, transferred to the article and easily separated from the template wafer. Thus, the attached protrusions may be, e.g., micro-bumps or micro pillars on an IC chip or substrate, test probes on a probe head, or one or more cantilevered membranes in a micro-machine or micro-sensor or other micro-electro-mechanical systems (MEMS) formed without undercutting the MEMS structure.
1. A test probe head comprising:
a probe head substrate;
an array of probe tip attach pads, array pads being layered pads on a pitch at or less than fifty microns (50 μm); and
a probe tip soldered to each probe tip attach pad, each probe tip comprising:
a single base layer soldered to a probe tip attach pad,
a conductive layer with a pyramidal tip shape, said single base layer being electroplated to said conductive layer, and
a capping layer, said conductive layer being electroplated to said capping layer.
2. A test probe head as in claim 1 , wherein said each probe tip has a pyramidal shaped tip.
3. A test probe head as in claim 2 , wherein said each pyramidal shaped tip has a 1-50 μm diagonal from corner to corner.
4. A test probe head as in claim 1 , wherein said single base layer is nickel, said conductive layer is copper and said capping layer is nickel (Ni).
5. A test probe head as in claim 1 , wherein each layered pad comprises:
a pad base layer on said probe head substrate;
an interface layer on said pad base layer; and
an anti-oxidation layer on said interface layer.
6. A test probe head as in claim 5 , wherein said pad base pad layer is copper, said interface layer is nickel, and said anti-oxidation layer is gold.
7. A test probe head as in claim 1 , wherein the probe tips are soldered to the probe tip attach pads with a lead-free solder electroplated to said single base layer.
8. A test probe head as in claim 7 , wherein said lead-free solder is a tin/silver (Sn/Ag) solder.
9. A test probe head comprising:
a probe head substrate;
an array of probe tip attach pads, array pads being layered pads on a pitch at or less than fifty microns (50 μm); and
a probe tip soldered to each probe tip attach pad, each probe tip having a pyramidal shaped tip and comprising:
a single base layer soldered to a probe tip attach pad,
a conductive layer with a pyramidal tip shape, said single base layer being electroplated to said conductive layer, and
a capping layer of a material selected from nickel (Ni), cobalt (Co), iron (Fe), suitable refractory metal or an alloy thereof, said conductive layer being electroplated to said capping layer.
10. A test probe head as in claim 9 , wherein each layered pad comprises:
a pad base layer on said probe head substrate;
an interface layer on said pad base layer; and
an anti-oxidation layer on said interface layer.
11. A test probe head as in claim 10 , wherein the probe tips are soldered to the probe tip attach pads with a lead-free solder.
12. A test probe head as in claim 11 , wherein said single base layer is nickel, said conductive layer is copper and said capping layer is nickel (Ni).
13. A test probe head as in claim 12 , wherein said pad base pad layer is copper, said interface layer is nickel, and said anti-oxidation layer is gold.
14. A test probe head as in claim 11 , wherein said lead-free solder is a tin/silver (Sn/Ag) solder electroplated to said single base layer.
15. A test probe head as in claim 11 , wherein said each pyramidal shaped tip has a 1-50 μm diagonal from corner to corner.
16. A test probe head comprising:
a probe head substrate;
an array of probe tip attach pads, array pads being layered pads on a pitch at or less than fifty microns (50 μm), wherein each layered pad comprises:
a pad base layer on said probe head substrate,
an interface layer on said pad base layer, and
an anti-oxidation layer on said interface layer; and
a probe tip soldered to each probe tip attach pad with a lead-free solder electroplated to said single base layer, each probe tip having a pyramidal shaped tip and comprising:
a single base layer soldered to a probe tip attach pad,
a conductive layer with a pyramidal tip shape having a 1-50 μm diagonal from corner to corner, said single base layer being electroplated to said conductive layer, and
a capping layer of a material selected from nickel (Ni), cobalt (Co), iron (Fe), suitable refractory metal or an alloy thereof, said conductive layer being electroplated to said capping layer.
17. A test probe head as in claim 16 , wherein said single base layer is nickel, said conductive layer is copper and said capping layer is nickel (Ni).
18. A test probe head as in claim 17 , wherein said pad base pad layer is copper, said interface layer is nickel, and said anti-oxidation layer is gold.
19. A test probe head as in claim 18 , wherein said lead-free solder is a tin/silver (Sn/Ag) solder.