I-Connect007’s Nolan Johnson catches up with Sean Fleuriel, a chemist for MacDermid Alpha Electronics Solutions, and Richard Bellemare, director of electrolytic metalization, to discuss the SMTAI technical paper presented by Fleuriel, titled, “Pit Resistant Acid Copper Electroplating Process for Flash Etching.” Fleuriel and Bellemare highlight the challenges, processes, and conclusions from the paper, as well as which PCB fabricators are most likely to benefit from this new process.
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Nolan Johnson: Hi, Nolan Johnson for virtual Real Time with.. SMTAI, and today I am on the line with MacDermid Alpha’s Sean Fleuriel and Rich Bellemare. Sean is a chemist, and Rich is the director of electrolytic metallization. Gentlemen, welcome.
Sean Fleuriel: Hey, Nolan. Thanks for having us.
Rich Bellemare: Thanks a lot for having us. It’s a pleasure to be here.
Johnson: For me as well. Now, our topic of conversation for today is a paper that has been submitted to SMTA International. Sean, looking at the paper, you’re the principal author?
Fleuriel: Yes, I am.
Johnson: Tell me about the paper. The title is “Pit Resistant Acid Copper Electroplating Process for Flash Etching.” It’s pretty interesting.
Fleuriel: Yes, so this is related to a project that we were working on for a customer recently, and we discovered a new process that was new for our company. We wanted to put out a paper on it.
Johnson: Maybe just start with why pitting is a problem.
Fleuriel: Pitting is a problem that’s related to etching, or the etching process, which is used in between plating steps for a multi-layer buildup of different circuit boards. The etching is integral to the process, and the pitting is a defect that occurs when the etching process doesn’t occur evenly on the surface. Anytime there’s etching, there’s a possibility of pitting occurring. We wanted to create an acid copper system that was resistant to that potential issue.
Bellemare: Where this really comes in is as HDI applications evolve, and lines and spaces are getting tighter and tighter and tighter. When you do the final circuit formation, the appearance of any kind of defect on that circuit trace, as it’s getting smaller, means a much more awful outcome should that defect occur that a catastrophic failure of the circuitry because of that pit.
Johnson: Historically, back when the geometries were larger, you were talking about something that was a basic minor blemish. Now that minor blemish can be a major obstacle.
Johnson: You were working with a customer and, in the process, came up with a new process. Let’s talk about the process that’s outlined in your paper. How do you reduce this?
Fleuriel: Our customer highlighted that different electroplating solutions and systems performed differently in terms of pit resistance. That gave us a pathway to understanding that different organic additives and systems can be used to minimize or increase the pit formation. Based on that, we decided to tailor our additive packages to minimize the pit formation. And we were able to see the trends that our customer was seeing in our laboratory environment, so we could replicate it, control it with different factors, and then eventually reduce it to a great extent.
Johnson: This sounds to me like this is sort of an optimization process.
Fleuriel: Correct. It is an optimization, but we also needed to develop novel additives to address this since we didn’t have a product before that was tailored for this specific application.
Johnson: Let’s talk a little bit about your presentation. You’re presenting your paper, which is videotaped. Walk me through the outline for that just a bit.
Fleuriel: The presentation talks a little bit about the background of some other research that was done that focused on the mechanism of pit formation, and then that was what we followed as a guide to reduce the pit formation. I talk a little bit about that. I talk about where our system and where the industry standard of performance was and our steps towards improving it and how our process, the final product performs in comparison to that. Just an overview, but doesn’t delve too deeply into the mechanism because there is already research out there about that specific topic.
Johnson: Sean, what kind of results did your customers see?
Fleuriel: The customers saw a dramatic reduction in the formation of pits, which is consistent with what we saw in our laboratory. We’ve seen this in multiple locations. I don’t know the exact number of the locations that we’ve scaled it up at, but it’s been very consistent, and people have been very happy with the reduction in the pitting defect that they’ve seen.
Johnson: Rich, what kind of customer is this a good solution for?
Bellemare: Again, this is a customer that’s really kind of going towards more of the HDI, MSAP, and SAP type buildups, where, as I said, the lines and spaces are getting much finer and where the tolerance for these types of defects just cannot be tolerated.
Johnson: Correct me if I’m wrong, but it sounds like this fits really well where you’re still doing subtractive processing, but you’re right at a point where you might need to start looking at the process, right down there at the fine edge.
Bellemare: Correct. And where this is finding a lot of application is in a lot of the mobile communication equipment, handphones, and stuff like that.
Johnson: Great. This sounds really quite interesting and certainly a paper that I have enjoyed reading. It’s fun to do some chemistry stuff and follow up on that. Nice work, Sean.
Fleuriel: Thank you very much.
Johnson: This is one that will have great value to our readers.
Johnson: Gentlemen, thank you for taking the time.