Shielding for vertical probe heads
Crosstalk between probes in a vertical probe array is reduced by providing a grounded metal carrier disposed between the guide plates of the probe array. The metal carrier includes pockets that are laterally separated from each other by the metal carrier. Probes in different pockets are thereby electrically shielded from each other.
1. A vertical probe array configured to test an electrical device, the vertical probe array comprising:
a first guide plate;
a second guide plate;
two or more vertical probes, each of the vertical probes configured to pass through corresponding holes in the first and second guide plates, wherein the vertical probes are slidably disposed in the holes of the first and second guide plates, whereby the vertical probes are not affixed to the first guide plate and whereby the vertical probes are not affixed to the second guide plate;
a metal carrier disposed between the first and second guide plates;
wherein the metal carrier includes two or more pockets extending between the first and second guide plates, wherein the vertical probes are disposed in the two or more pockets;
wherein the metal carrier is grounded, whereby electrical isolation between probes in different pockets is improved.
2. The vertical probe array of claim 1 , wherein the first and second guide plates are electrically insulating.
3. The vertical probe array of claim 1 , wherein the first and second guide plates are electrically conductive.
4. The vertical probe array of claim 3 , wherein the first and second guide plates include metal layers deposited on an insulating substrate.
5. The vertical probe array of claim 3 , wherein the first and second guide plates include metal layers bonded to an insulating substrate.
6. The vertical probe array of claim 3 , wherein at least one of the vertical probes is one or more signal probes that are electrically insulated from the first and second guide plates.
7. The vertical probe array of claim 6 , wherein the signal probes include at least one multipath probe having a signal path for electrical signals that is insulated from the first and second guide plates and a ground path that is electrically connected to the first and second guide plates, wherein the signal path and the ground path are both part of the multipath probe.
8. The vertical probe array of claim 1 , wherein a ground connection of the metal carrier is located within 1 mm of a signal probe being isolated from other probes by the metal carrier.
9. The vertical probe array of claim 1 , wherein probe to probe crosstalk from one pocket of the metal carrier to another pocket of the metal carrier is reduced by 10 dB or more in a predetermined frequency range.