A Printed Electronics Roadmap With Komori’s Doug Schardt

Estimated reading time: 8 minutes

At SEMICON West this year, I had the pleasure of speaking with Doug Schardt, Komori America’s director of Printed Electronics Business, who discussed how Komori has evolved from a traditional printing company to a leader in modern printing solutions, with a specific focus on printed electronics (PE) equipment and materials. He details the potential for Komori’s gravure offset printing, research into conductive inks, and why he believes AI chips are driving the future of printed electronics.

Marcy LaRont: I understand that Komori just celebrated its 100th anniversary in 2023. Would you share some background on the company, and its evolution into what you are doing today in PE?

Doug Schardt: Komori started as a manufacturing company in Japan that decided to get into printing. Now, 100 years ago, printing wasn't the same as it is now. Komori always tried to be innovative and a little bit ahead of the curve, but was really focused on printing.

Over that century, Komori didn’t just focus on printing in the traditional sense—magazine printing or book printing. It expanded into many other areas, such as currency printing. We also do inkjet, web offset, and roll-to-roll. Basically, if it says “printing” on it, Komori had a hand in it, and we learned how to design great equipment and sell in each market.

Long story short, we know about all styles of printing. We know what's really effective over here and what’s really effective over there. Now, we can apply all that knowledge to today's modern manufacturing equipment, where we can achieve some dramatic results. With printed electronics, we got into that because it’s called “printed” electronics. We thought, “We know how to print; we'll just print electronics now instead of words or pictures. We knew we could bring all our technical knowledge together to start producing equipment that satisfies today's printed electronics demands.

LaRont: Are you still involved in a wide array of printing?

Schardt: Yes, we're still involved with all of it. We're still doing the currency and security presses, because there's a big global security market for IDs, passports, and things like that. We still do web printing as well as inkjet and offset.

LaRont: Now you’re working with conductive inks, very sophisticated machinery, and all sorts of different kinds of materials and substrates. When did this shift happen, and what was the thought process behind it?

Schardt: Yes, the machines are different, the process is different, and what we're trying to achieve is different. The level of refinement is much different. Now it's getting so refined and so small that in order to do anything really valuable today in PE (printed electronics), you have to be very accurate and very precise.

LaRont: I imagine the refinement level in printed electronics is different than even five years ago.

Schardt: Or even six months ago. That’s probably been our steepest learning curve during our transition from the general printing market to the PE market. You need to have a whole different skill set about understanding what's required, what's acceptable, and what's not acceptable.

LaRont: It's a heck of a ramp-up. When did you start moving over into this segment?

Schardt: The first machine for PE was built in 2013, but it had been in development since, I believe, 2010, as we had already determined that we wanted to pursue this. Somebody at Komori back then was looking ahead, thinking, “We have to have a space in this market.”

That first machine was produced in 2013, and I should note that I'm referring to gravure offset printing at this point. The other printed electronic machines we produce such as screen printing and vacuum coaters, started around 1972. Those would be what we consider the more traditional printing processes for manufacturing PC boards. We're still actively selling and supporting that equipment. But gravure offset printing has the ability to quickly print much smaller features than other printing techniques, leading to applications in semiconductor back end fab.

LaRont: Please explain some of the technology behind gravure offset printing.

Schardt: It's an approach to additively printing whatever we need for a circuit or package or anything else. For example, it could be very thin traces, a chip fanout or a micro bump and gravure offset is substrate independent. You can print on flexible or rigid materials, and you can use a variety of different pastes or inks, so you're not tied to any one product. Of course, the properties of the ink or paste have to be acceptable to the machine. But other than that, you're not handcuffed.

LaRont: Does Komori provide inks too?

Schardt: Technically, no, but we're co-developing some inks. That's the “material” part of the PE story. Gravure offset printing is frequently used in R&D, and as new applications are developed, they lead to more questions and challenges. We are currently aiming for improved conductivity with the inks.

LaRont: What is your strategy for printed electronics going forward?

Schardt: We’re looking at the PCB market, what's going on in the U.S., and the CHIPS Act, and projecting what will happen. It looks like there will be growth into additively printing some PCBs, especially if they retain their flexibility. There is a lot of research being done to get there, but it is ongoing.

One of the big barriers is the conductivity of the printed ink. It is conductive, but not like pure copper. We are working to develop an ink that has conductivity close to that of solid copper, if not equal to it in performance. Therein lies the challenge, but we've got some really smart people working on it.

Commercialization, or lack thereof, is what keeps the features required in many electronics today from being what they are. Most of our electronics are already designed and being produced so we have to offer a compelling reason to change their design. While we now have equipment that can additively print very small features, electronic devices still have to be designed to utilize those small features. Right now, advanced AI chips are actually hurting the flexibility issue, because they're stacking up and then the circuits are not flexible anymore. If we can achieve this ink with copper-like conductivity, then the whole PCB market should open up to an alternative manufacturing process, something that will allow manufacturers to do different things packaging these AI chips.

Normally, if a wide conductive trace is required, you can do that with screen or aerosol jet printing. But everything is getting very small. Gravure offset will give us the ability to print these extremely small features with precision and repeatability.

Depending on the application, you may need a thicker ink film than what can be achieved in just one print cycle. In this case, you can simply make a second pass through the machine, or a third or fourth pass, until you achieve the desired height. You may need six passes for a solder bump on a semiconductor chip to attach a micro LED. The machine is accurate enough to print over the same pattern every time to build the height of the ink. I don't want to take anything away from other processes, because they all have their place.

LaRont: Not every process is right for everything and there will still be a place for our more traditional processes.

Schardt: Exactly. This new process is proven to be reliable enough to go into commercialized manufacturing, and then the question will be, “What equipment will be suitable for the speed and accuracy to do X?” As I said, we can do a lot of stuff with inkjet, but it won’t be good enough to get down to those finer feature levels and be competitive.

LaRont: How fine and how thin does gravure offset allow you to get?

Schardt: Typically, when talking about conductive ink, you should be around 5 microns. The height that one pass will give you is about 2 microns of ink film. For most usage, getting down around 5 is enough. We are able to print micro solder bumps directly onto a wafer using Type 10 solder paste, and the particle size in Type 10 solder paste is 1–3 microns.

LaRont: What is the standard particle size of solder paste?

Schardt: While there is a range, Type 7 is typical. The flake size in a Type 7 is significantly bigger than that of a Type 9 or Type 10. The flake size literally determines how fine you can print because it's dependent on the metallic flake in the ink. If the flake is 10 microns, you can't print an 8-micron dot because the flake is bigger than what you want to print. When you get to Type 10, where Komori is today, the maximum flake size is 3 microns, so we can print pretty fine.

Theoretically—and it's more than theoretical because you can actually do it—you could print a 4-micron feature with Type 10 because a 3-micron flake will still fit in there. That’s okay for testing, but for production, that would be risky.

We're always working toward getting smaller, but it's also material-dependent. We have to wait for better materials to be able to get much smaller, but the gravure offset machine is mechanically capable of printing smaller features.

LaRont: Doug, regarding the dispensing technology, how is the flake deposited onto the device?

Schardt: Gravure offset starts with an engraved plate. It’s a nickel or glass plate, and whatever you want to print is literally engraved into it. Then the paste gets applied across the plate. A little squeegee blade goes over and pushes all that ink into the engravings, and then a second blade on the reverse stroke cleans off the top of the plate.

You’re left with an engraved plate with ink in the engraving. That plate will be moved under a metal cylinder that has a blanket on it. That cylinder will be lowered down to roll over the engraving, which pulls the ink out of the engraving, leaving it on the blanket. It’s a special blanket designed to absorb some of the solvent out of the ink. When we do that, it locks the ink into the shape it's supposed to be in. Once the ink is on the blanket, the engraved plate will move out of the way. From the other side of the cylinder, another plate with your substrate will come in underneath. The cylinder does the same thing, rolling over it, but in this case, it's putting the ink on the substrate.

That means that it’s comparatively fast. If we're doing a big area with silver ink, I would say it would be one pass of 30 seconds or so, and this whole area's done, whether it’s a circuit or micro bumps, no matter how many dots you have. But if you are printing a Type 10 paste, then that paste is so thick that we have to slow everything down, because the paste doesn't flow. We really have to push it and let it sit in there, so it might take a few minutes to do a pass. We believe we can go into commercialization now and get good yields and low cost, but I would suggest pretesting on one of our machines.

LaRont: I wanted to ask you about conductive inks generally. I attended a technical session a while back, and they were talking about using all the different elements on the periodic table. It doesn't always have to be copper. Are you seeing that as well?

Schardt: There's experimentation with different metals now for conductivity, and although we're not really involved with the different metals, we are watching it. We work with numerous universities overseas that conduct this type of evaluation, and we’re listening to what they're saying. The same thing is going on with semiconductors, the platform itself. A lot of different things are being tried because we will need some different options for what's coming up, especially for the heat dissipation on some of these chips.

LaRont: I agree. What is Komori America’s place in this particular market?

Schardt: We are focused on two main markets: printed circuit board fabrication and backend semiconductor packaging. Komori America is talented, but quiet. Right now, our focus is more about getting the word out: “Hey, we're here and we have these great capabilities.” If anyone would like to reach out to us about doing some testing, we encourage that.

LaRont: When do you see commercialization happening? Is there a timeline?

Schardt: Yes, but it isn't my timeline. Our customers have a timeline, and they’re the ones pushing, saying, “We will do this, so come along for the ride and help us with this.” Our gravure offset customers are driving the progress. I think if we can improve the conductivity of the copper printed inks many things will change quickly.

LaRont: What do you think will be the most influential printed electronics technology in the next five to 10 years? Can you see that now?

Schardt: It is very difficult to see what's coming next. I thought we were starting to tap out on Moore's Law with semiconductors and then there was another advancement. There are many brilliant people exploring new and innovative ways of designing electronics that could be significantly different from what we know today. I would hope in the next 10 years or so, we would be exploring one of those new ways.

LaRont: That’s a great place to wrap up, Doug. Thank you so much for speaking with me. Best of luck to you and Komori, and I know we’ll talk again.

Schardt: Thank you, Marcy.