Issue link: https://iconnect007.uberflip.com/i/1207026
FEBRUARY 2020 I SMT007 MAGAZINE 61 Feinberg: We see manufacturing coming back from China to the U.S., but we'll see what hap- pens. Suzuki: At the same time, China is trying to develop new technology. Feinberg: What do you see for the future of sol- der mask? What would you like to see as the next innovation or improvement? Suzuki: There are a lot of different versions of the packaging, and the PCB area is evolving right now with HDI and high-density. It also evolved to SLP substrate PCBs. So far, we have dry-film material for the IC packaging, and that's only the form factor, but if we would like to apply the dry film material toward PCB- type applications, we need it to be thicker and keep the good resolution at the thicker form factor. Right now, we have no good capability for making the thicker film material. Thicker film with higher capability is one direction, and another is high temperature and high volt- age resistance. A lot of companies are moving that direction in terms of automotive, autono- mous vehicles, and industrial applications. Feinberg: One other thing that we were always fighting to improve was the geometry of the sidewalls, especially the sidewall after expo- sure and development. We tried to get very straight sidewalls but with a little bit of a curve outward at the very bottom to help enhance adhesion; of course, you would need a scan- ning electron microscope to see it. Is that some- thing that you're still working toward, or are the sidewalls adequate with what you're doing? Suzuki: That requires not only ourselves but our customers on the process establishment, but that is one direction we need to move toward. Feinberg: Chemically, it was always a challenge for my research people to get the correct geom- etries on the sidewalls and still maintain good exposure rates. Suzuki: And a good exposure speed. Feinberg: What frequency of light exposure? Suzuki: 365 nm. Feinberg: I see some movement toward addi- tive circuits. Additive manufacturing has been around since the '60s, but it never took off. Now, with the demand for finer lines and more components, there is one company, in particu- lar, that's doing some amazing work on addi- tive with 3D printing. Do you see any kind of movement toward additive circuits yet in Japan, Korea, or Taiwan? Suzuki: In Asia, the trend toward additives is not there yet. But there is movement toward the inkjet-type photoresist, and we already have some interest from our customers about that. So far, Europe has the highest interest in terms of additive manufacturing, as well as the U.S. Feinberg: There are some advantages, but when we were doing 20-mil lines and spaces, it didn't matter. Now, it's a tiny fraction of that, especially with all the portable devices.