Method and apparatus for providing active compliance in a probe card assembly
View Patent ↗A probe card assembly can comprise a first source of compliance and a second source of compliance. The probe card assembly can further comprise a controller, which can be configured to apportion a total compliance demand placed on the probe card assembly between the first source of compliance and the second source of compliance.
1. A probe card assembly comprising:
a probe head assembly comprising a plurality of probes disposed to make electrical connections with terminals of an electronic device while the terminals are pressed against and moved an over travel distance past first contact with the probes, wherein the probes are resilient and provide a first source of compliance to absorb a first portion of the over travel;
a mounting structure for mounting the probe card assembly to a test housing for housing the electronic device, wherein the probe head assembly is coupled to the mounting structure; and
moving means for moving the probe head assembly with respect to the mounting structure to provide a second source of compliance to absorb a second portion of the over travel, wherein the moving means is coupled to the mounting structure.
2. The probe card assembly of claim 1 , wherein the moving means comprises:
a plurality of sensors;
a plurality of actuators; and
a controller configured to control the actuators in accordance with signals from the sensors.
3. The probe card assembly of claim 2 , wherein the sensors comprise devices each configured to produce a signal that corresponds to a force on one of the probes.
4. The probe card assembly of claim 2 , wherein the sensors comprise devices each configured to produce a signal that corresponds to a distance between a portion of the probe head assembly and a corresponding portion of the electronic device.
5. The probe card assembly of claim 1 further comprising:
a wiring substrate comprising an electrical interface to a tester for controlling testing of the electronic device, wherein the wiring substrate is coupled to the mounting structure and the moving of the probe head assembly with respect to the mounting structure is also with respect to the wiring substrate; and
flexible electrical connections electrically connecting the wiring substrate to the probe head assembly, wherein the electrical interface is electrically connected to the probes.
6. The probe card assembly of claim 5 , wherein the flexible electrical connections electrically connect the wiring substrate to the probe head assembly as the moving means moves the probe head assembly with respect to the mounting structure.
7. The probe card assembly of claim 1 , wherein the moving means also couples the probe head assembly to the mounting structure.
8. The probe card assembly of claim 1 , wherein the moving means comprises actuators each configured to move a different portion of the probe head assembly with respect to the mounting structure.
9. The probe card assembly of claim 8 , wherein each actuator is configured to push a corresponding portion of the probe head assembly away from the mounting structure.
10. The probe card assembly of claim 9 , wherein the moving means further comprises a biasing means for biasing the probe head assembly toward the mounting structure.
11. The probe card assembly of claim 8 , wherein each actuator is configured to selectively push a corresponding portion of the probe head assembly away from the mounting structure and pull the corresponding portion of the probe head assembly toward the mounting structure.
12. The probe card assembly of claim 1 further comprising a space directly between the mounting structure and the probe head assembly, and wherein the moving means moves the probe head assembly with respect to the mounting structure within the space.
13. The probe card assembly of claim 1 further comprising:
a sensor configured to sense a force on at least one of the probes, wherein the force corresponds to a compliance demand on the probe card assembly; and
a controller programmed to allocate a portion of the compliance demand to the moving means.
14. The probe card assembly of claim 13 , wherein the controller is further programmed to control the moving means to move the probe head assembly with respect to the mounting structure sufficiently to meet the portion of the compliance demand.
15. The probe card assembly of claim 14 , wherein the portion of the compliance demand is greater than zero but less than the compliance demand on the probe card assembly.
16. The probe card assembly of claim 14 , wherein the portion of the compliance demand is an amount of the compliance demand on the probe card assembly that exceeds a predetermined threshold.
17. The probe card assembly of claim 14 , wherein the portion of the compliance demand is a predetermined percentage of the compliance demand on the probe card assembly.