Issue link: https://iconnect007.uberflip.com/i/1221561
MARCH 2020 I PCB007 MAGAZINE 21 Johnson: Any other highlights? Bowerman: It was fun working on the project because we used a lot of expertise from our people with both tech service and application backgrounds. We have facilities called global de- velopment application centers (GDACs). There are seven of them globally that work with met- allization products. Most of them have some form of pilot line capacity for running full-size panels. We use those sites to make improve- ments in the equipment for our customers. We had a chance to work the processes out before we had the customer spend the money on the first mass production lines. Thanks to that pro- cess, we developed a couple of unique things that we had never specifically used before for direct metallization. Johnson: Interesting. How does Blackhole fit in- to the MacDermid Alpha product portfolio? Bowerman: MacDermid is involved in both elec- troless copper metallization as well as this direct metallization and the step that goes beyond into electrolytic. We look at everything as a complete package for reliability. Reliability is a big topic right now in the United States, so we're very sensitive about the interface where the electro- lytic copper is either on the target pad or on the electroless. We're doing a lot of work right now to ensure that we're meeting the expectations of designers building stacked microvias. Johnson: Bill, thanks for setting the stage for your paper. Bowerman: Thank you very much. PCB007 times, we talk to them about direct metalliza- tion as the seed layer because we're more of a coating process than a redox reaction. When they have exotic materials—there could be any- thing from PTFE to hydrocarbons—we're not very sensitive to the changes in surface energy on those materials. Johnson: This whole situation does seem to put pressure on the existing job-shop fabricators to bring their processes up-to-date. Bowerman: Yes. Our industry has changed so much in the last 20 years. If you're looking at a new process line, you have to keep that in mind. If I'm buying a line that is going to be on my floor for the next 15–20 years, how much is this industry going to continue to change and evolve? Johnson: Are there any paper highlights that you'd like to bring to readers attention? Bowerman: There are a couple of main points. We know that we're working with ultra-thin foil now to get our line width and spacing down. We're now at 30 and 30 in the industry; maybe some of the advanced packaging applications can go a little bit below that. But also we're working with a very square sidewall profile on the traces. The dominant theme in the metalliza- tion, whether electroless copper or direct metal- lization, is to have a very precisely controlled mi- croetch as we go through the metallization line because we have as low as three microns of foil when we start. We walked through the process by completely reviewing the equipment package that we're recommending, with the goal of hav- ing this very tightly controlled amount of etch. Johnson: Right. Are you delivering those tight tolerance results? Bowerman: We have it in mass production to- day in Asia. There are multiple lines running MSAP today with this three-micron foil. In oth- er words, we've already gone past the release point. We're in the commercialization of it, and we have production experience with it. We had a chance to work the processes out before we had the customer spend the money on the first mass production lines.