Wissel: It is. Dr. Mike Bixenman will refer to it as the Z-axis. Five years ago, it was not uncommon to have something with a 3-, 4-, 5-mil gap, where the cleaner could easily penetrate underneath. Now components are often flush to the surface with only a half a mil standoff for LGAs or QFNs. QFNs are especially challenging packages because they have a large ground plane underneath which obstructs fluid from flushing under the package from one side to the other.
Goldman: How can it get in there where you need it—and then get the cleaner out again. Another challenge.
Wissel: Again, it comes back to collaboration. For a successful cleaning process, I use the analogy of a three-legged stool. The machine maker must be involved, along with the solder paste company and the cleaning agent company. Because between those three things, the customer has to have a soldering material that they can build a reliable part with. Then they have to have a cleaning agent that will remove the flux, and a process that successfully implements that cleaning agent. Without all three of those things working together, success is unlikely.
There is continuous R&D on all fronts: solder paste material sets, on cleaning material agent material sets, and innovation in the machines to deliver that cleaning agent to where the soil is. It’s a fun industry, and no day is ever the same. No day is dull.
Goldman: Very interesting! Ram, thanks again for speaking with me today.
Wissel: You are welcome.
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