Issue link: https://iconnect007.uberflip.com/i/1140547
22 DESIGN007 MAGAZINE I JULY 2019 fracture may appear at higher temperatures but "heal" itself again upon cooling; nonethe- less, this often results in field failures. It's in- sidious because the problem pops up after rou- tine test procedures are successful. This issue is a big focus for this event because the team is working with IPC and the industry to de- fine the problem, collect data to see how big of a problem it is, and find ways to mitigate it. Microvias have been—and will continue to be—a reliable and important feature in circuit boards, so it's important to figure out this con- cern quickly. Shaughnessy: You all had a great line-up for the conference. What were some of the highlights in your opinion? Sandy-Smith: It is difficult to single out a few moments because I enjoyed all of the presenta- tions. I felt the keynote by John Bauer of Col- lins Aerospace was quite interesting. My fa- vorite part is always the panel discussions be- cause the interaction drives the conversation to the heart of the matter (both for the micro- vias panel and the surface reliability panel). We truly have some great experience among the speakers at IPC conferences, and they are so appreciated. Shaughnessy: I noticed that some of the speak- ers said that PCB designers have a role in de- signing boards—vias in particular—to be more reliable. Reliability seems to involve everyone in the supply chain. Sandy-Smith: Absolutely! Companies that make Class 3 electronics can only be success- ful when they are detailed about quality at ev- ery level of the supply chain—from design to incoming goods quality, monitoring their as- sembly processes, inspection, and testing of all the goods they produce. It is a major effort and one we all benefit from, for instance, when we're trusting the plane we're flying on to the next conference. Shaughnessy: Is there anything else you'd like to add? Sandy-Smith: Stay tuned for our next confer- ence November 5–7 in Minneapolis, Minneso- ta—our first IPC Electronics Materials Forum. This conference will have a wide variety of topics, and it's perfect for people who are pas- sionate about materials like I am. As always, we're also planning for IPC APEX EXPO 2020 where you'll see presentations from all facets of the electronics industry with the latest stud- ies and novel strategies for circuit boards and assemblies. Shaughnessy: Thanks for speaking with me, Brook. Sandy-Smith: Thank you, Andy. DESIGN007 To make modern communications possible, today's mobile devices make use of components that use acous- tic waves to filter or delay signals. However, current so- lutions have limited functionalities that prevent further miniaturization of mobile devices and constrain the avail- able communication bandwidth. Now, a research team led by Chiara Daraio, Caltech professor of mechanical engineering, has developed pho- nonic devices that could find uses in new kinds of sen- sors, improved cellphone technologies applied physics, and quantum computing. The phononic devices include parts that vibrate ex- tremely fast, moving back and forth up to tens of millions of times per second. The team developed these devices by creating silicon nitride drums that are just 90-nm thick. The drums are arranged into grids with different grid pat- terns having different properties. These findings open opportunities to design new devic- es—such as phononic transistors and radio-frequency isola- tors—based on phonons instead of electrons. Their findings appear in two papers published in Nature Nanotechnology and Nature. (Source: California Institute of Technology) Phononic Devices Could Allow Smaller Mobile Devices