Method of reconstructing electrical probes
View Patent ↗A probe, comprising: a shank region having a top surface integrally connected to a bottom surface of a conical region; a pyramidal tip region having a base surface integrally connected to a top surface of the conical region; and wherein the base surface of the pyramidal tip region is contained within a perimeter of the top surface of the conical region. Also a method of fabricating the probe and a method of probing devices under test.
1. A method comprising:
providing a probe comprising a shank region having a top surface integrally connected to a bottom surface of a conical region, said conical region tapering to a point;
ion milling a pyramidal tip region having a base and an apex into an upper portion of said conical region, said ion milling removing surface portions of said upper portion of said conical region and removing said point, said apex becoming a new point; and
after said ion milling, a lower portion of said conical region remaining,
wherein said shank region has a uniform diameter, said lower portion of said conical region tapers from said shank region to said pyramidal tip region at a first angle, and said pyramidal tip region tapers from a base of said pyramidal tip region to said apex at a second angle.
2. The method of claim 1 , wherein said ion milling is performed using a focused ion beam tool.
3. The method of claim 1 , wherein said pyramidal tip region has N sides wherein N is a positive integer between 3 and 8 and further comprising:
ion milling one of said N sides;
rotating said probe by 360/N degrees; and
repeating said milling and said rotating until all N sides have been ion milled.
4. The method of claim 1 , wherein said pyramidal tip region has four sides, and further comprising:
ion milling a first of said four sides;
rotating said probe 180°;
ion milling a second of said four sides;
rotating said probe 90°;
ion milling a third of said four sides;
rotating said probe 180°; and
ion milling a fourth of said four sides.
5. The method of claim 1 , wherein said perimeter of an exposed top surface of said lower portion of said conical region is circular, and every vertex of a perimeter of a base surface of said pyramidal tip region touches said perimeter of said exposed top surface of said conical region.
6. The method of claim 1 , wherein said probe is formed from a metal selected from the group consisting of tungsten, tungsten-rhenium, beryllium-copper and palladium alloy.