Hybrid probe for testing semiconductor devices
View Patent ↗A hybrid probe design is presented that includes a torsion element and a bending element. These elements allow the probe to store the displacement energy as torsion or as bending. The probe includes a base, a torsion element, a bending element, and a tip. The probe elastically deforms to absorb the displacement energy as the probe tip contacts the DUT contact pad. The bending element absorbs some of the displacement energy through bending. Because the torsion element and the bending element join at an angle, a portion of the displacement energy is transferred to the torsion element causing it to twist (torque). The torsion element can also bend to accommodate the storage of energy through torsion and bending. Adjusting the position of a pivot can alter the probe's energy absorption characteristics. One or more additional angular elements may be added to change the energy absorption characteristics of the probe.
1. A probe card for testing a semiconductor device, comprising:
a substrate;
a hybrid probe connected to the substrate, the probe comprising a base that is connected to the substrate, a torsion element connected to the base, a bending element connected to the torsion element through a union angle, and a probe tip connected to the bending element; wherein the probe elastically stores displacement energy while the probe tip contacts the device; and
wherein the torsion element is adapted to twist such that the torsion element elastically stores a first portion of displacement energy and the bending element is adapted to bend such that the bending element elastically stores a second portion of the displacement energy;
a pivot connected to the substrate, wherein a portion of the probe is configured to contact the pivot; and
wherein a ratio between the first portion of displacement energy and the second portion of displacement energy is in the range from about 15:85 to 85:15.
2. The probe card of claim 1 , wherein the ratio between the first portion of displacement energy and the second portion of displacement energy is in the range from about 30:70 to 50:50.
3. The probe card of claim 1 wherein the bending element and the torsion element are manufactured using photolithography.
4. The probe card of claim 3 wherein the torsion element is manufactured using a first photolithographic layer, and the bending element is manufactured using a second photolithographic layer.
5. The probe card of claim 1 wherein the torsion element is comprised of a first material and the bending element is comprised of a second material.
6. The probe card of claim 5 wherein the first material has a higher Young's Modulus than the second material.
7. The probe card of claim 5 wherein the first material has a lower Young's Modulus than the second material.
8. The probe card of claim 5 wherein the first material has substantially the same Young's Modulus as the second material.
9. The probe card of claim 1 wherein the torsion element is constructed to achieve a polar moment of inertia that allows the torsion element to twist such that the first portion of displacement energy is greater than the second portion of displacement energy.
10. The probe card of claim 1 wherein the bending element is constructed to achieve a moment of inertia that allows the bending element to bend such that the second portion of displacement energy is greater than the first portion of displacement energy.
11. The probe card of claim 1 wherein the torsion element or bending element is a split bar.
12. The probe card of claim 1 wherein the torsion element is adapted to bend such that the torsion element elastically stores a third portion of the displacement energy through bending.
13. The probe card of claim 1 wherein the bending element is adapted to twist such that the bending element elastically stores a third portion of the displacement energy through torsion.
14. The probe card of claim 1 wherein the pivot is connected to the substrate at a position, and wherein the position of the pivot is selected to achieve a desired characteristic that is selected from a group consisting of: scrub length, probe pressure, packing density, probe failure from material fatigue, uniform stress distribution, and combinations thereof.
15. The probe card of claim 1 wherein the union angle comprises an angle.
16. The probe card of claim 1 , wherein the torsion element comprises an additional angular element that is comprised of an angle.
17. The probe card of claim 1 , wherein the bending element comprises an additional angular element that is comprised of an angle.
18. The probe card of claim 1 , wherein the torsion element comprises an additional angular element that is comprised of an angle and the bending element comprises an additional angular element that is comprised of an angle.
19. The probe card of claim 16 wherein the angle is in the range from about 90 to 270 degrees.
20. The probe card of claim 19 wherein the angle is selected to achieve a desired characteristic that is selected from a group consisting of: scrub length, probe pressure, packing density, probe failure from material fatigue, uniform stress distribution, and combinations thereof.
21. The probe card of claim 1 , wherein the bending element is comprised of a nickel alloy.
22. The probe card of claim 1 , wherein the torsion element is comprised of a nickel alloy.
23. The probe card of claim 1 wherein the probe further comprises a probe post connected to the probe tip, wherein the surface of the probe post is manufactured such that the probe post is configured to be optically distinguished from the probe tip.
24. The probe card of claim 1 wherein the bending element is wider and thinner than the torsional element.
25. The probe card of claim 24 wherein the bending element is comprised of a first material with a Young's Modulus and the torsion element is comprised of a second material with a Young's Modulus, wherein the first material's Young's Modulus is less than the second material's Young's Modulus.
26. The probe card of claim 1 wherein the bending element is shorter than the torsional element.
27. The probe card of claim 26 wherein the bending element is comprised of a first material with a Young's Modulus and the torsion element is comprised of a second material with a Young's Modulus, wherein the first material's Young's Modulus is greater than the second material's Young's Modulus.
28. The probe card of claim 1 wherein the portion of the probe contacts the pivot while the probe tip contacts the device.