Issue link: https://iconnect007.uberflip.com/i/1143487
64 PCB007 MAGAZINE I JULY 2019 Williams: So, you were kind of the R&D lead on developing that technology and getting it to become a viable technology here in Tucson. What was that process like, and what were the challenges? Chiem: From a technology standpoint, there weren't any major challenges, as this technolo- gy is 20–30 years old and very mature. I used to work at Honeywell back in the '90s where we built flex as a chip carrier every day and talked about 3-mil lines and spaces 20 years ago. Williams: It may be new to Prototron, but it's old to you? Chiem: Exactly. We were doing some crazy PCB technology 20 years ago in Costa Mesa, California. Williams: And did you have to do anything here from an equipment set standpoint, including changes to processes, or was it just a matter of using different raw materials? Chiem: Of course, flex and rigid-flex require a different material set, but mainly, we just needed to develop custom frames, or material handling fixtures, to process the thin materials through Prototron's standard, rigid PCB con- veyorized equipment. The Tucson shop was set up for standard, rigid multilayer produc- tion, and the equipment set reflected that. Williams: Were there any obstacles you had to overcome because the shop had never built flex here before? Did you have to re-educate the workers or develop new processes and re- train people on how to handle this type of ma- terial? Chiem: We also had to modify our processes and procedures to adapt to flex processing. Then, it was just a matter of blending the cur- rent chemistry and equipment with the new frames to make flex a reality here at Prototron. As we've progressed, we've gained knowledge on how to develop the in-house flex capabil- ity. I also needed to train people, write speci- fications, upgrade the procedures, and make sure everybody was familiarized with the new processes. Williams: Are you also looking at doing rigid- flex? Chiem: We have developed the processes and ran test orders successfully, so I am confident we can build rigid-flex here right now. It's not difficult. Williams: I love your confidence. I understand you're currently working on another project with some very small mechanically drilled holes also. Chiem: Correct. Kim wanted me to work on mechanically drilling 4-mil microvias using our current Schmoll drilling equipment. Williams: And that would be controlled depth drilling of the microvias? Chiem: Yes, 4-mil diameter by 5 mils deep. Williams: Earlier, you mentioned that mechan- ically drilling 4-mil holes is not that big of a deal; it's the fluid dynamics of getting the chemistry through a blind hole of that size hole. Chiem: Therefore, we need to put in some new, different chemistry, as the current conven- tional chemistry that we have right now is not meant for this application. Williams: So, it's pretty standard microvia stuff, but you are doing it mechanically instead of laser drilling. Excellent. What else is on your to-do list for Prototron in advancing their tech- nology levels? Chiem: I think we are open to doing R&D col- laboration with other companies on advanced technology. For instance, I am working with an organization in Toronto, Canada, to devel- op a very advanced PCB design. In that way, we have a mutual interest between the two