Spring Probe WLCSP Probe Head CCC – ISMI Characterization Is Not Enough

A recognized standard for evaluating the CCC (current carrying capacity) of an interconnect used at wafer probe has been the ISMI Probe Council Current Carrying Capability Measurement Guideline, published by International SEMATECH Manufacturing Initiative in 2009. The ISMI test is a relatively simple way to observe the interconnect force degradation as a function of current applied. The guideline evaluates at what point the contact sees a 20% force reduction. This 20% force reduction, means that the contact has been permanently deformed, and this is therefore a truly destructive test.

The ISMI guideline has been used to measure the CCC of spring probes for several years, and it does provide a value that can be used to compare one technology to another. The resulting value, however, does not describe the CCC for the actual test application. It will be shown that in controlled laboratory experiments, probes run at or near the ISMI CCC values in simulated test environments prematurely fail by taking a permanent set. Data from several configurations and probe types will be shown that behave in this manner.

Version: March 2019
Presented by: Valts Treibergs
Presented at: TestConX