Issue link: https://iconnect007.uberflip.com/i/1507822
16 PCB007 MAGAZINE I SEPTEMBER 2023 I would be cautious about the "build it and they will come" idea, but that doesn't mean you can't enter that space. ere's certainly plenty of volume needed there. Johnson: Which market sectors are most driving this move toward UHDI? I would say mobile, and Internet of ings— anything that's handheld, such as watches, phones, and tablets. All those are tending to drive harder on the ultra HDI space. ere are newer markets that have been developing. It's anything that is small, even your earbuds for sound. Medical keeps getting smaller probes, wearables—those are all driv- ing the ultra HDI. Johnson: With ultra HDI, the concerns are becom- ing more complex, there- fore, materials must become even more specialized, and even discussing the need for the glass, the materials are more expensive, yet they're going into products that are so very price sensitive. Right, and even lower Dk- or Df-type resin systems are going into even more things that were traditionally considered consumer- type products; 5G, 6G, etc., are demanding a better performing material both from the cop- per and from the dielectric perspective, elec- trically. What we normally wouldn't have con- sidered in that space is getting pressured to be in that space. at goes back to some of the earlier com- ments on the properties of the material being driven and that becomes a bigger problem, be- cause if you had a 0.25-millimeter pitch pack- age vs. a 1-millimeter package, your CTE mis- match or your adhesion challenges are differ- ent. So, on an infrastructure basis, you don't expect someone to push your service stack over on the floor and have it dropped, but on a phone, watch, or any number of these head- sets, people will drop them, so you need to be robust against the user. Matties: Darren, what final advice can you share with the industry around this topic or otherwise? Work with your suppliers. Consider the mate- rials and the properties. It's a difficult balance. Don't be afraid to ask questions. Regardless of the supplier's name, in general, they have re- sources to help and give you insights. You don't always need to learn every lesson on your own the first time. If you rely on your suppliers for information, it can help you avoid some of the pitfalls that come with new technologies. Johnson: Sounds to me like talking to your suppliers means not just talking to your fabricator but going further upstream to the other key materials as well. Co r r e c t . S o m e O E Ms a r e working all the way up into the copper and glass suppliers. Gen- erally, your raw material suppliers have a pretty good grasp on that. You need to understand the assembly perspective, have a raw material understand- ing, and know your fabricators and substrate suppliers. ey are capable of certain things and have a capability that will give you good yields. ey have advanced capabilities for people who are willing to give up a little bit on yield to try and advance those technologies. Matties: Darren, thank you so much for your insights. Always great talking with you. PCB007 Reference 1. 'Advanced Technologies for Printed Circuit Board Fabrication and Raw Materials', SMTAI Keynote presentation, 2023. Medical keeps getting smaller probes, wearables— those are all driving the ultra HDI.