Probe bonding method having improved control of bonding material
View Patent ↗In assembly of probe arrays for electrical test, a problem can arise where a bonding agent undesirably wicks between probes. According to embodiments of the invention, this wicking problem is alleviated by disposing an anti-wicking agent on a surface of the probe assembly such that wicking of the bonding agent along the probes toward the probe tips is hindered. The anti-wicking agent can be a solid powder, a liquid, or a gel. Once probe assembly fabrication is complete, the anti-wicking agent is removed. In preferred embodiments, a template plate is employed to hold the probe tips in proper position during fabrication. In this manner, undesirable bending of probes caused by introduction or removal of the anti-wicking agent can be reduced or eliminated.
1. A method for fabricating a probe assembly comprising:
forming a bonding cavity;
passing a plurality of probes through the bonding cavity;
filling the bonding cavity with a bonding agent;
disposing an anti-wicking agent on a surface of the bonding agent in the bonding cavity; and
curing the bonding agent in the bonding cavity; and removing the anti-wicking agent.
2. The method of claim 1 further comprising providing a guide plate assembly having a first guide plate separated from a second guide plate by a spacer, the guide plate assembly defining the bonding cavity.
3. The method of claim 2 further comprising disposing holes in the first and second guide plates.
4. The method of claim 3 further comprising disposing the probes in the holes.
5. The method of claim 4 further comprising providing gaps between the probes and the guide plates at the holes between 5 μm and 40 μm.
6. The method of claim 4 comprising lateral spacing of the probes less than about 150 μm.
7. The method of claim 3 further comprising aligning the first and second guide plates using corresponding first and second hole patterns.
8. The method of claim 3 wherein the filling the bonding cavity comprises introducing the bonding agent through the holes.
9. The method of claim 1 further comprising facing probe tip sections the same way relative to the guide plate assembly.
10. The method of claim 1 comprising boding with a material selected from the group consisting of epoxy, thermally set material, molten plastic, and injection molding material.
11. The method of claim 1 further comprising:
providing a probe tip template; and
engaging a tip section of each of the plurality of probes with the probe tip template prior to disposing the anti-wicking agent.
12. The method of claim 11 wherein the probe tip template comprises a material selected from the group consisting of polyimide, ceramic, and metal.
13. The method of claim 1 wherein curing comprises heating.
14. The method of claim 1 wherein removing the anti-wicking agent comprises vacuuming out the anti-wicking agent.
15. The method of claim 1 further comprising cleaning the probe assembly via ultrasonic cleaning.
16. The method of claim 1 wherein the anti-wicking agent comprises a powder.
17. The method of claim 16 wherein the bonding agent does not substantially wick into the powder.
18. The method of claim 1 wherein the anti-wicking agent comprises talc.
19. The method of claim 1 wherein the anti-wicking agent comprises starch flour.
20. The method of claim 1 wherein the anti-wicking agent comprises a powder having a particle size of about 3 μm.
21. The method of claim 1 further comprising compacting the anti-wicking agent.
22. The method of claim 1 wherein the disposing the anti-wicking agent is performed with a syringe capable of delivering the powder.
23. The method of claim 1 wherein the anti-wicking agent comprises a gel.
24. The method of claim 23 wherein the gel comprises a silicone based gel.
25. The method of claim 23 wherein the gel and bonding agent are substantially immiscible.
26. The method of claim 1 wherein the anti-wicking agent comprises a liquid.
27. The method of claim 26 wherein the liquid comprises lithography compatible masking fluid.
28. The method of claim 26 wherein the liquid and bonding agent are substantially immiscible.