Direct metalized guide plate
Improved electrically conductive guide plates for vertical probe arrays are provided by patterning a thin metal layer disposed on an insulating substrate. Holes passing through the guide plate for guiding probes can be electrically connected or isolated from each other in any pattern according to the deposition of the metal. Such structures can include several distinct ground and/or voltage planes. Furthermore, passive electrical components can be included in the guide plate, by patterning of the deposited metal and/or by integration of passive electrical components with the deposited metal traces.
1. A guide plate for a probe array for testing electrical devices, the guide plate comprising:
an electrically insulating ceramic substrate having a hole pattern corresponding to a predetermined probe pattern;
a patterned metal layer disposed on the electrically insulating ceramic substrate such that at least two holes of the hole pattern are electrically connected to each other, and such that at least two holes of the hole pattern are electrically insulated from each other;
wherein the guide plate is configured to provide mechanical support for probes passing through the holes of the hole pattern;
wherein the guide plate is configured to have the probes pass through the holes of the hole pattern without being affixed to the holes of the hole pattern;
further comprising one or more passive component structures disposed to provide one or more compensating impedances between holes of the hole pattern, wherein the one or more passive component structures are each connected to two or more parts of the patterned metal layer.
2. The guide plate of claim 1 , wherein a thickness of the patterned metal layer is 10 microns or less.
3. The guide plate of claim 1 , wherein the one or more passive component structures are selected from the group consisting of: integrated capacitors, discrete component capacitors, integrated inductors, discrete component inductors, integrated resistors, and discrete component resistors.
4. A probe array comprising:
a top guide plate according to claim 1 ;
a bottom guide plate according to claim 1 ;
a probe array including two or more probes, wherein each probe of the probe array passes through corresponding holes in the top guide plate and in the bottom guide plate;
wherein at least one of the probes of the probe array is a ground probe making electrical contact to the top guide plate and to the bottom guide plate;
wherein at least one of the probes of the probe array is a signal probe that is electrically insulated from the ground probe.
5. The probe array of claim 4 , wherein the one or more compensating impedances of the top and bottom guide plates are configured to improve an impedance match for probing a device under test with the signal probe and the ground probe.
6. The probe array of claim 5 , further comprising one or more intermediate guide plates disposed between the top guide plate and the bottom guide plate;
wherein each intermediate guide plate comprises:
a) an electrically insulating ceramic substrate having a hole pattern corresponding to a predetermined probe pattern;
b) a patterned metal layer disposed on the electrically insulating ceramic substrate such that at least two holes of the hole pattern are electrically connected to each other, and such that at least two holes of the hole pattern are electrically insulated from each other; and
c) one or more passive component structures disposed to provide one or more compensating impedances between holes of the hole pattern;
wherein each probe of the probe array passes through corresponding holes in the one or more intermediate guide plates; and
wherein the one or more compensating impedances of the one or more intermediate guide plates are configured to improve the impedance match for probing a device under test with the signal probe and the ground probe.
7. The guide plate of claim 1 , wherein the passive component structure is a capacitor provided by a gap between a signal hole and a ground part of the patterned metal layer connected to a ground hole of the predetermined probe pattern.
8. The guide plate of claim 1 , wherein the passive component structure is a capacitor provided by a gap between a signal part of the patterned metal layer connected to a signal hole of the predetermined probe pattern and a ground part of the patterned metal layer connected to a ground hole of the predetermined probe pattern.
9. The guide plate of claim 8 , wherein the gap is configured as a spacing between two interdigitated metal regions.
10. The guide plate of claim 1 , wherein the passive component structure is a discrete component capacitor connected between a signal part of the patterned metal layer connected to a signal hole of the predetermined probe pattern and a ground part of the patterned metal layer connected to a ground hole of the predetermined probe pattern.
11. A method of making a guide plate for a probe array for testing electrical devices, the method comprising:
providing an electrically insulating ceramic substrate having a hole pattern corresponding to a predetermined probe pattern;
depositing and patterning a metal layer on the electrically insulating ceramic substrate such that at least two holes of the hole pattern are electrically connected to each other, and such that at least two holes of the hole pattern are electrically insulated from each other;
wherein the guide plate is configured to provide mechanical support for probes passing through the holes of the hole pattern;
wherein the guide plate is configured to have the probes pass through the holes of the hole pattern without being affixed to the holes of the hole pattern;
wherein the guide plate further comprises one or more passive component structures disposed to provide one or more compensating impedances between holes of the hole pattern, wherein the one or more passive component structures are each connected to two or more parts of the patterned metal layer.
12. The method of claim 11 , wherein a thickness of the metal layer is 10 microns or less.