Vertical probe array having sliding contacts in elastic guide plate
A probe array having decoupled electrical and mechanical design constraints on the probes is provided. Each probe is a two-part structure with the two parts able to stay in electrical contact with each other as the parts slide up and down with respect to each other. The probes are disposed in through holes of an elastic matrix, each probe having its corresponding hole. The probes engage with the elastic matrix such that a restoring force in response to vertical probe compression is provided by the elastic matrix. With this approach, electrical and mechanical design are much more decoupled than in conventional spring probe design. The elastic matrix provides the mechanical compliance and restoring force, while the parts of the probe determine its current carrying capacity and electrical bandwidth.
1. A probe array for making temporary electrical contact to a device under test, the probe array comprising:
two or more probes; and
an elastic matrix configured as a sheet having at least one elastomer layer and including an array of through holes, wherein each of the two or more probes is disposed in a corresponding one of the through holes, and wherein a vertical direction is perpendicular to the elastic matrix;
wherein each probe of the two or more probes includes a first part and a second part configured to make a sliding electrical contact with each other as the first part and the second part move with respect to each other along the vertical direction;
wherein each probe of the two or more probes engages with the elastic matrix such that a restoring force in response to vertical probe compression is provided by the elastic matrix;
wherein a tip to tip length of the two or more probes is between 250 μm and 750 μm, and wherein an electrical bandwidth of the two or more probes is at least 100 GHz.
2. The probe array of claim 1 , wherein the elastic matrix includes embedded ceramic particles.
3. The probe array of claim 1 , wherein the elastic matrix includes a multi-layer structure.
4. The probe array of claim 3 , wherein one or more layers of the multi-layer structure are metal layers configured to electrically connect some of the two or more probes to each other.
5. The probe array of claim 3 , wherein the multi-layer structure includes a ceramic plate configured to define lateral probe positions.
6. The probe array of claim 1 , wherein the two or more probes include at least one symmetric probe having no scrub motion of a probe tip as the symmetric probe is vertically compressed.
7. The probe array of claim 1 , wherein the two or more probes include at least one asymmetric probe having a scrub motion of a probe tip as the asymmetric probe is vertically compressed.
8. The probe array of claim 1 , wherein the two or more probes include at least one multi-prong probe where a contact force between probe parts increases as the multi-prong probe is vertically compressed.
9. The probe array of claim 1 , wherein at least one of the two or more probes is adhesively affixed to the through hole of the elastic matrix that it corresponds to.
10. The probe array of claim 1 , further comprising a rigid frame configured to laterally surround the elastic matrix.
11. The probe array of claim 1 , wherein the probe array is configured for multi-die probing, and wherein the elastic matrix includes one or more slots disposed to align with die boundaries.
12. The probe array of claim 1 , wherein the through holes of the elastic matrix are disposed at an angle relative to the vertical direction, whereby a scrub motion of probe tips is provided as the probes are vertically compressed.
13. The probe array of claim 12 , wherein the angle is in a range from 5 to 15 degrees.