Issue link: https://iconnect007.uberflip.com/i/1527952
66 PCB007 MAGAZINE I OCTOBER 2024 When you look at that process in terms of water usage, going through using LMI, and then creating the electroless on the panel, LMI allows you to eliminate a lot of the process line that sits in front of the electroless tank, which addresses significant water reduction and a reduction in the use of some chemicals. But you will still be plating copper back onto the panel, so you will run both processes. I think the environmental sustainability factor is negli- gible. However, this technology plays very well with non-halogen materials, and where every- one wants or needs to be halogen-free, this is a solid process that provides good adhesion to those materials. Nolan: Where does ASC fit into this? Are you still in the R&D stage or moving to an adop- tion phase with some of your customers? We are using this process in ASC manufactur- ing and have quite a few active projects. It's becoming more mainstream as our custom- ers' design teams say they need it for very fine- pitch BGAs. We've started to see 0.5-millime- ter pitch driving the move to finer features. e designers are faced with the challenge of how to route in those scenarios only having a 3-mil line or space, so you must achieve a smaller trace and space. ese designers understand that the technology is there and has been done for a long time. Anyone who has a mobile phone in their hand knows that the technol- ogy and reliability have been proven. Over- all, I think the design community is seeing this and is designing it into new projects. We're seeing a lot of interest from that aspect. We're seeing it in the defense primes as well. As we get into the ultra-fine pitch BGAs, they need to use that, and they need to route it out. ey are starting to recognize that if they can't route it out, the boards get much more complicated and require many more layers. Nolan: Since this is fully online at ASC, is the customer bringing a job to you and requiring the process, or are you reviewing the job and recommending it? Some customers know they want to use the technology. In other cases, we'll recommend it. RF is very important here. It has been chal- lenging to achieve very tight impedance con- trol on some RF designs. If a customer has a design that is already 20+ layers with blind vias upon blind microvias, we are looking at this technology. In general, there has been a lot of interest from our customers in LMI™ plating technology. It is really starting to progress in the market. Nolan: How well placed is ASC in this technology? Who else is doing it? ere are about a half-dozen shops in the U.S. able to provide this level of technology by my count. It's a problem because every customer wants to have multiple sources. As the demand increases, more fabricators will be able to build this technology. Our benefit is that we've been at it longer and have already worked through the challenges that one encounters moving to these very fine line technologies. It is more than just creating ultra-fine lines. Nolan: John, thank you for helping us under- stand this technology better. Happy to oblige. PCB007 Microsection of a six-layer structure using the technology test structure.