Issue link: https://iconnect007.uberflip.com/i/1140547
90 DESIGN007 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 technol- ogy 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 reeducate the workers or develop new processes and retrain people on how to handle this type of material? 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 too. 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 list of to do for Prototron in advancing their technology 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